Certified Hemodialysis Bio-Medical Technician (CHBT) — Questions and Answers

Question 1: What is the primary purpose of equipotential bonding in a hemodialysis patient care area?

To ensure all conductive surfaces are at the same electrical potential, eliminating current flow between them (Correct answer)
To ground the blood pump separately from the dialysis machine
To increase electrical power capacity for multiple machines
To provide a return path for dialysate current

Correct answer: To ensure all conductive surfaces are at the same electrical potential, eliminating current flow between them

Equipotential bonding connects all exposed conductive parts to a reference point so no voltage difference exists between them, preventing current from flowing through a patient who touches two surfaces.

Question 2: What is the consequence of using dialysate with too low a sodium concentration?

Hyponatremia, hypotension, muscle cramps, and risk of cerebral edema (Correct answer)
Hypertension and volume overload
Metabolic alkalosis
Hyperkalemia

Correct answer: Hyponatremia, hypotension, muscle cramps, and risk of cerebral edema

Hypotonic dialysate pulls sodium from the blood, causing hyponatremia that leads to osmotic fluid shifts, cramping, hypotension, and potentially dangerous cerebral edema.

Question 3: If a patient requests that their dialyzer not be reused, what is the appropriate response?

Allow the patient to opt out only if they pay the higher cost of single-use dialyzers themselves
Honor the patient's request; patients have the right to refuse dialyzer reuse and must be informed of their rights (Correct answer)
Explain that reuse is a standard practice and the patient does not have a choice
Document the request but continue reuse since it is medically equivalent

Correct answer: Honor the patient's request; patients have the right to refuse dialyzer reuse and must be informed of their rights

Patient autonomy requires that all patients be informed about reuse practices and given the right to refuse. CMS ESRD regulations mandate that facilities inform patients of their reuse policy and respect refusals. Coercion or ignoring opt-out requests is prohibited.

Question 4: In the event of a power failure during hemodialysis, what is the first priority?

Return blood to the patient using the hand crank or gravity if available, and ensure patient safety (Correct answer)
Wait for power to restore since machines automatically resume on battery backup
Disconnect the patient immediately and discard all blood in the circuit
Increase the dialysate flow rate to compensate for reduced treatment time

Correct answer: Return blood to the patient using the hand crank or gravity if available, and ensure patient safety

During power failure, blood in the extracorporeal circuit must be returned to the patient to prevent blood loss and circuit clotting. Most machines have a manual blood pump crank for this purpose. Patient safety is the primary concern.

Question 5: Under AAMI guidelines, what is the maximum number of times a dialyzer can be reused before mandatory discard?

There is no universal maximum; reuse continues as long as the dialyzer passes TCV and integrity testing at each reprocessing (Correct answer)
A maximum of 10 uses for all dialyzers regardless of performance
A maximum of 3 uses for high-flux dialyzers and 5 for low-flux
25 uses for automated reprocessing systems and 10 for manual

Correct answer: There is no universal maximum; reuse continues as long as the dialyzer passes TCV and integrity testing at each reprocessing

AAMI standards specify performance criteria (TCV ≥80%, integrity test passage) rather than a fixed use limit. The dialyzer is discarded when it fails any performance criterion. However, many facilities set internal policy limits (often 12–20 uses) as an additional safety measure.

Question 6: During biomedical equipment inspection, an insulation resistance test on a dialysis machine reads 0.5 megaohm. What does this indicate?

Acceptable insulation within normal range
Excellent insulation integrity
Normal reading for all dialysis machines
Degraded insulation that may pose a safety hazard (Correct answer)

Correct answer: Degraded insulation that may pose a safety hazard

Medical equipment insulation should typically measure at least 1–2 megaohms; a reading of 0.5 megaohm suggests insulation breakdown and potential leakage current risk requiring further evaluation.

Question 7: What is uremia?

The syndrome caused by accumulation of uremic toxins when kidneys fail to adequately filter the blood (Correct answer)
A urinary tract infection caused by urea-splitting bacteria
Elevated blood urea nitrogen from a high-protein diet alone
Increased urine output in early kidney disease

Correct answer: The syndrome caused by accumulation of uremic toxins when kidneys fail to adequately filter the blood

Uremia is the clinical syndrome resulting from the retention of nitrogenous and other waste products normally excreted by healthy kidneys.

Question 8: A patient develops sudden rigors (shaking chills) and high fever 20 minutes into hemodialysis. This is most consistent with:

Normal autonomic response to the initiation of dialysis in some patients
Pyrogenic reaction from endotoxin contamination in the dialysate or water (Correct answer)
Hypoglycemia due to glucose removal by the dialysate
Hyperkalemia from potassium movement during dialysis

Correct answer: Pyrogenic reaction from endotoxin contamination in the dialysate or water

Pyrogenic reactions (fever, rigors, hypotension) occurring early in dialysis are caused by bacterial endotoxins or gram-negative bacteria in contaminated water or dialysate. Treatment must be stopped, the water system investigated, and the patient managed supportively.

Question 9: A dialysis machine displays a low arterial pressure alarm. Which condition is LEAST likely to cause this?

Kinked arterial blood line
High dialysate conductivity (Correct answer)
Blood pump running too fast for access flow
Collapsed access site

Correct answer: High dialysate conductivity

Low arterial pressure alarms are caused by flow restrictions or inadequate access blood supply; dialysate conductivity does not directly affect arterial line pressure.

Question 10: How often should a dialysis technician perform a visual check of the extracorporeal blood circuit during treatment?

Only at the start and end of each session
Once per hour when the patient is stable
At least every 30 minutes throughout the treatment (Correct answer)
Only when the machine alarms

Correct answer: At least every 30 minutes throughout the treatment

Regular monitoring of the blood circuit at least every 30 minutes is a standard safety practice. It allows early detection of clotting, blood leak, or line disconnection before a serious event occurs.

Question 11: What is the CDC's recommended approach for surface disinfection in dialysis units between patients?

Clean all external surfaces of the dialysis machine and chair with an EPA-registered disinfectant between each patient use (Correct answer)
Disinfect surfaces with 70% ethanol, which does not require EPA registration
Use sterile water only to avoid chemical contact with patients
Wipe visible blood only; routine disinfection is not required between stable patients

Correct answer: Clean all external surfaces of the dialysis machine and chair with an EPA-registered disinfectant between each patient use

CDC and CMS require EPA-registered hospital disinfectant cleaning of all external machine surfaces, chair, and patient-contact areas between every patient. This includes the blood pump housing, touchscreen, armrests, and IV poles.

Question 12: What does 'standard precautions' require in a dialysis setting?

Using full PPE only for patients with known bloodborne pathogen infections
Standard precautions apply only to patients on isolation for confirmed infections
Wearing gloves only when handling needles; gowns are optional for routine care
Treating all blood, body fluids, non-intact skin, and mucous membranes as potentially infectious regardless of patient diagnosis (Correct answer)

Correct answer: Treating all blood, body fluids, non-intact skin, and mucous membranes as potentially infectious regardless of patient diagnosis

Standard precautions apply universally to all patients. This includes hand hygiene, appropriate PPE (gloves for blood/fluid contact, gown/eye protection when splash risk exists), safe needle handling, and environmental cleaning.

Question 13: Which lab value should be monitored in a patient receiving continuous heparin anticoagulation during hemodialysis to detect over-anticoagulation?

Blood urea nitrogen (BUN)
Serum phosphorus
Activated Partial Thromboplastin Time (aPTT) or Activated Clotting Time (ACT) (Correct answer)
Serum albumin

Correct answer: Activated Partial Thromboplastin Time (aPTT) or Activated Clotting Time (ACT)

aPTT and ACT are the primary coagulation tests used to monitor heparin effect. Supratherapeutic values indicate over-anticoagulation and risk of bleeding. aPTT is used for systemic monitoring; ACT for point-of-care assessment during treatment.

Question 14: Which laboratory value is most commonly used to assess dialysis adequacy (Kt/V)?

Creatinine
Potassium
Bicarbonate
Blood urea nitrogen (BUN) (Correct answer)

Correct answer: Blood urea nitrogen (BUN)

BUN is the primary marker used to calculate Kt/V because urea is freely filtered and its clearance reflects small-molecule uremic toxin removal.

Question 15: Which staff member is primarily responsible for ensuring compliance with dialyzer reprocessing protocols?

The trained dialyzer reprocessing technician, supervised by the facility's biomedical or reprocessing supervisor (Correct answer)
The attending nephrologist, who must approve each reprocessed dialyzer
The charge nurse, who must verify each dialyzer before it is filled with disinfectant
The patient's primary care physician, who must authorize reuse in the prescription

Correct answer: The trained dialyzer reprocessing technician, supervised by the facility's biomedical or reprocessing supervisor

Reprocessing is performed by specifically trained technicians under the supervision of a biomedical or reprocessing supervisor. The technician is responsible for following the AAMI/ANSI RD47 standard procedures, performing quality tests, and proper documentation.

Question 16: Which patient condition is a contraindication to standard heparin anticoagulation during hemodialysis?

Prior AVF surgical creation within the last 12 months
Mild thrombocytopenia (platelet count 120,000)
Active intracranial hemorrhage or recent neurosurgery (Correct answer)
Stable chronic kidney disease stage 4

Correct answer: Active intracranial hemorrhage or recent neurosurgery

Active intracranial bleeding is an absolute contraindication to heparin use. Anticoagulation would expand the hemorrhage. In such cases, heparin-free dialysis or regional citrate anticoagulation (for CRRT) must be used.

Question 17: A CHBT technician notices a patient's access site is bleeding excessively after needle removal. What is the first step?

Apply direct pressure to the site with sterile gauze (Correct answer)
Document the finding and wait for it to resolve on its own
Elevate the arm above heart level without touching the site
Reinsert the needle to stop the bleeding

Correct answer: Apply direct pressure to the site with sterile gauze

Direct pressure with sterile gauze is the immediate first response to control bleeding from a vascular access site. Continuous pressure for the appropriate time is required, and the nurse must be notified.

Question 18: What is the recommended storage condition for unused dialyzer cartridges?

Refrigerated at 2–8°C
Submerged in sterile saline
Room temperature, away from direct sunlight, within manufacturer expiration date (Correct answer)
Frozen until use

Correct answer: Room temperature, away from direct sunlight, within manufacturer expiration date

Dialyzers should be stored at controlled room temperature, protected from light and moisture, and used before the manufacturer's expiration date.

Question 19: The primary reason hemodialysis patients are restricted in dietary potassium intake is that:

Potassium causes access site infections
Dialysis machines cannot remove potassium
High potassium decreases dialyzer efficiency
The kidneys can no longer excrete potassium, causing dangerous accumulation between treatments (Correct answer)

Correct answer: The kidneys can no longer excrete potassium, causing dangerous accumulation between treatments

Without functional kidneys, dietary potassium accumulates in the blood between sessions, risking fatal hyperkalemia and cardiac arrest before the next treatment.

Question 20: All of the following conditions are associated with chronic kidney failure EXCEPT:

low hemoglobin.
hyperphosphatemia.
hypoparathyroidism. (Correct answer)
hyperkalemia.

Correct answer: hypoparathyroidism.

Chronic kidney failure often leads to hyperparathyroidism, not hypoparathyroidism. Damaged kidneys cannot properly activate Vitamin D, leading to low calcium levels, which in turn stimulates the parathyroid glands to overproduce parathyroid hormone (PTH) in an attempt to raise calcium. This condition is known as secondary hyperparathyroidism.

Question 21: What does a 'temperature alarm' on a hemodialysis machine indicate, and why is it dangerous?

The dialysate temperature is outside the 35–38°C range; overheated dialysate causes hemolysis and can be fatal (Correct answer)
The room temperature has exceeded comfort levels for the patient
The blood warmer circuit has cooled below normal temperature
The RO water temperature is too cold, affecting membrane efficiency

Correct answer: The dialysate temperature is outside the 35–38°C range; overheated dialysate causes hemolysis and can be fatal

Dialysate temperature must remain in the 35–38°C range. Dialysate above 42°C causes thermal hemolysis (red blood cell destruction), releasing potassium and causing fatal hyperkalemia. The machine bypasses overheated dialysate to drain automatically.

Question 22: Under CMS ESRD regulations, who is responsible for ensuring the dialysis prescription is appropriate and orders are updated?

The biomed technician
The patient's nephrologist (physician of record) (Correct answer)
The dialysis nurse in charge
The facility administrator

Correct answer: The patient's nephrologist (physician of record)

The nephrologist is the physician of record responsible for reviewing adequacy data, updating treatment prescriptions, and authorizing all medical orders for each patient.

Question 23: What is the function of the transducer protector on a hemodialysis machine?

Controls the ultrafiltration rate
Measures arterial blood pressure
Filters dialysate before it enters the dialyzer
Prevents blood contamination of the pressure monitoring port (Correct answer)

Correct answer: Prevents blood contamination of the pressure monitoring port

The transducer protector is a hydrophobic filter that prevents blood or fluid from entering the machine's pressure transducer, protecting against cross-contamination.

Question 24: Which action is part of a two-patient identifier check in the dialysis setting?

Confirming the patient's chair number matches their appointment slot
Asking the patient their address and checking their insurance card
Verifying the patient's name and date of birth before connecting them to the dialyzer (Correct answer)
Matching the dialyzer serial number to the machine model

Correct answer: Verifying the patient's name and date of birth before connecting them to the dialyzer

Two patient identifiers (typically name and date of birth) must be confirmed before initiating treatment. This prevents wrong-patient errors and is a universal healthcare safety standard.

Question 25: Acetate was largely replaced by bicarbonate as the dialysate buffer primarily because:

Acetate metabolism caused hemodynamic instability, vasodilation, and was poorly tolerated by some patients (Correct answer)
Acetate caused hyperkalemia
Bicarbonate is cheaper to produce
Regulatory agencies mandated the switch

Correct answer: Acetate metabolism caused hemodynamic instability, vasodilation, and was poorly tolerated by some patients

Acetate requires hepatic metabolism to generate bicarbonate and its metabolites cause vasodilation, contributing to intradialytic hypotension and fatigue — bicarbonate dialysate is better tolerated.

Question 26: What is 'tight heparin' dosing in hemodialysis?

Double-strength heparin used for patients with high clotting tendency
Heparin administered only as a single bolus with no continuous infusion
Subcutaneous heparin given 2 hours before dialysis instead of IV administration
A protocol using the minimum effective heparin dose, with lower bolus and infusion rates than standard, used for patients at moderate bleeding risk (Correct answer)

Correct answer: A protocol using the minimum effective heparin dose, with lower bolus and infusion rates than standard, used for patients at moderate bleeding risk

Tight heparin (also called minimal heparinization) uses reduced bolus and infusion rates to achieve ACT of 140–170 seconds rather than the standard 150–200 seconds. It is used for patients with moderate bleeding risk to balance clotting prevention and hemorrhage risk.

Question 27: Which regulatory standard requires dialysis facilities to have a written emergency preparedness plan?

AAMI RD52
FDA 21 CFR Part 820
OSHA 29 CFR 1910.119
CMS Emergency Preparedness Rule (42 CFR Part 494) (Correct answer)

Correct answer: CMS Emergency Preparedness Rule (42 CFR Part 494)

The CMS Emergency Preparedness Rule mandates that ESRD facilities maintain written emergency plans addressing hazard vulnerability, communication, policies, and training.

Question 28: An occupational exposure report for a dialysis technician involved in a needlestick from a patient with unknown HIV status should include:

The technician's next scheduled shift and whether they feel well enough to return to work
The time/date of exposure, type of needle, source patient information, employee's vaccination status, and post-exposure prophylaxis offered (Correct answer)
A description of the blood pump speed at the time of the incident
Only the employee's name and date; patient information is protected by HIPAA

Correct answer: The time/date of exposure, type of needle, source patient information, employee's vaccination status, and post-exposure prophylaxis offered

Occupational exposure reports must be complete and timely. Source patient information (with consent for testing) is critical for determining post-exposure prophylaxis (PEP) for HIV and baseline testing for HBV/HCV. HIPAA permits disclosure for treatment-related purposes.

Question 29: A hemodialysis machine alarms with a 'blood leak' alert. What is the immediate action?

Reset the alarm and complete the treatment since false alarms are common
Increase transmembrane pressure to force the leak to seal itself
Reduce the blood flow rate and observe to see if the alarm clears
Stop the blood pump, clamp the blood lines, and do not return blood to the patient until the dialyzer is inspected (Correct answer)

Correct answer: Stop the blood pump, clamp the blood lines, and do not return blood to the patient until the dialyzer is inspected

A blood leak alarm means dialyzer membrane rupture is suspected. The blood pump must be stopped immediately, lines clamped, and the dialysate inspected for pink or red color. Blood must NOT be returned until a true leak is ruled out.

Question 30: Which of the following is correct regarding documentation after a hemodialysis-related emergency or adverse event?

Verbal reporting to the charge nurse is sufficient; written documentation is optional
Only the attending physician is responsible for documenting adverse events
Documentation is required only if the patient required hospitalization after the event
An incident report must be completed in addition to the medical record entry, detailing the event, response, and outcome (Correct answer)

Correct answer: An incident report must be completed in addition to the medical record entry, detailing the event, response, and outcome

Adverse events require both medical record documentation (clinical timeline, interventions) and a facility incident report (root cause, contributing factors). Incident reports are used for quality improvement and regulatory compliance, not as part of the medical record.

Question 31: According to Ohm's Law, if a dialysis machine has a leakage current pathway with a resistance of 500,000 ohms and is connected to a 120V supply, what is the leakage current?

240 microamperes (Correct answer)
24 milliamperes
2.4 milliamperes
24 microamperes

Correct answer: 240 microamperes

Using I = V/R: 120V ÷ 500,000Ω = 0.00024 A = 240 microamperes, which exceeds the 100 µA AAMI limit.

Question 32: Peritoneal dialysis (PD) differs from hemodialysis in which of the following ways?

PD cannot be done at home
Sterile dialysate is not required for PD
PD access is by an intra-abdominal catheter (Correct answer)
PD requires both vascular access and abdominal access

Correct answer: PD access is by an intra-abdominal catheter

Peritoneal dialysis (PD) utilizes the peritoneum, a membrane lining the abdominal cavity, as a natural filter. To access this cavity, a permanent catheter is surgically placed into the abdomen. This allows dialysate fluid to be introduced and drained, facilitating waste removal within the patient's own body.

Question 33: What action should be taken when the blood pump stops unexpectedly during hemodialysis?

Assess the circuit immediately for clotting, check all alarms, identify the cause, and restart per protocol if safe to do so (Correct answer)
Continue treatment using gravity flow through the venous line
Disconnect the patient immediately and discard the circuit
Restart the pump at maximum speed to re-establish flow quickly

Correct answer: Assess the circuit immediately for clotting, check all alarms, identify the cause, and restart per protocol if safe to do so

An unexplained blood pump stop requires immediate assessment. The circuit must be inspected for clotting. If the circuit is intact and the cause identified (e.g., power glitch, line kink), the pump can be restarted per protocol. Prolonged stasis leads to circuit clotting.

Question 34: What is the purpose of the distribution loop in a dialysis facility water system?

To store reserve dialysate concentrate for emergency use
To mix product water with dialysate concentrate before delivery to the machine
To return used dialysate to the pre-treatment tank for re-purification
To continuously circulate purified water to all dialysis stations, preventing bacterial stagnation (Correct answer)

Correct answer: To continuously circulate purified water to all dialysis stations, preventing bacterial stagnation

The distribution loop keeps purified water moving continuously at a velocity that prevents biofilm formation. Dead legs (stagnant sections) in the loop are a primary source of bacterial contamination.

Question 35: What is the purpose of dedicated supplies (e.g., non-shared supply trays) in dialysis units?

To comply with CMS requirements for individual patient billing of supplies
To prevent cross-contamination between patients by ensuring supplies touched by one patient are not used for another (Correct answer)
To prevent staff from accidentally using expired supplies stored in the common area
To reduce the cost of supplies by limiting what is stocked at each station

Correct answer: To prevent cross-contamination between patients by ensuring supplies touched by one patient are not used for another

Shared supply carts and trays are a known route for cross-contamination in dialysis units, particularly for HBV. Each patient station should have dedicated, single-use supplies that are not returned to the common supply area once brought to the station.

Question 36: Which sign indicates possible stenosis in an arteriovenous fistula?

Bright red arterial blood returning via the venous needle
A palpable pulse throughout the entire fistula length
High venous pressure during dialysis combined with a decreased thrill distal to the stenosis (Correct answer)
Normal bruit quality with consistently achieved blood flow rates

Correct answer: High venous pressure during dialysis combined with a decreased thrill distal to the stenosis

Stenosis restricts flow, causing elevated venous pressure as blood backs up behind the obstruction. The thrill (vibration) is diminished distal to the narrowing. This warrants referral for imaging (fistulogram) and possible angioplasty.

Question 37: Under OSHA's Bloodborne Pathogens Standard, dialysis facilities are required to offer hepatitis B vaccination to employees:

Only to full-time employees
At the employee's expense if they choose to receive it
Only after an exposure incident occurs
At no cost to the employee, within 10 working days of initial assignment to a job with occupational exposure (Correct answer)

Correct answer: At no cost to the employee, within 10 working days of initial assignment to a job with occupational exposure

OSHA's Bloodborne Pathogens Standard (29 CFR 1910.1030) mandates that employers provide HBV vaccination free of charge to all employees with occupational blood exposure within 10 days of job assignment.

Question 38: What is the 'venous pressure alarm' high limit designed to detect in a hemodialysis circuit?

Excessive anticoagulation causing the blood to become too thin
Obstruction in the venous return line such as a kinked tube, clotted filter, or access stenosis (Correct answer)
Depletion of the heparin syringe in the infusion pump
Low blood pressure in the patient requiring fluid bolus

Correct answer: Obstruction in the venous return line such as a kinked tube, clotted filter, or access stenosis

A high venous pressure alarm indicates resistance to blood returning to the patient. Common causes include a kinked venous line, clotted venous chamber, needle malposition, or access stenosis. It must be investigated promptly to prevent circuit rupture.

Question 39: When mixing a bicarbonate concentrate from dry powder, which precaution is essential?

Mix 24 hours in advance and refrigerate
Use tap water for cost savings
Add the powder to hot water to speed dissolution
Use water that meets dialysis water quality standards and mix per manufacturer instructions to ensure sterility and correct concentration (Correct answer)

Correct answer: Use water that meets dialysis water quality standards and mix per manufacturer instructions to ensure sterility and correct concentration

Bicarbonate solutions support bacterial growth rapidly; they must be prepared with purified water, used promptly (within manufacturer-specified timeframes), and mixed per protocol.

Question 40: What does the 'A concentrate' (acid concentrate) typically contain that is NOT in the 'B concentrate' (bicarbonate concentrate)?

Phosphate buffer
Sodium chloride only
Calcium, magnesium, potassium, glucose, and acetic acid or citric acid (Correct answer)
Sodium bicarbonate only

Correct answer: Calcium, magnesium, potassium, glucose, and acetic acid or citric acid

The acid concentrate contains the divalent cations (calcium, magnesium), potassium, glucose, and an acid (acetic or citric) to keep them in solution; the B concentrate contains sodium bicarbonate.

Question 41: What is the primary cause of anemia in chronic kidney disease (CKD)?

Vitamin B12 deficiency
Iron overload
Chronic blood loss from dialysis access
Insufficient production of erythropoietin by diseased kidneys (Correct answer)

Correct answer: Insufficient production of erythropoietin by diseased kidneys

The failing kidney produces inadequate erythropoietin, the hormone that stimulates red blood cell production, leading to normocytic normochromic anemia.

Question 42: What is the correct method for testing ground wire integrity on hemodialysis equipment using a biomedical safety analyzer?

Pass at least 25 amperes DC through the ground conductor and measure resistance (Correct answer)
Apply 120V AC between the chassis and ground pin
Use a megohmmeter at 500V to test ground resistance
Measure resistance using a standard digital multimeter on ohms setting

Correct answer: Pass at least 25 amperes DC through the ground conductor and measure resistance

AAMI/ANSI standards require ground wire testing with a high-current source (typically 25 A) to stress the ground conductor and accurately measure resistance, as low-current ohmmeters cannot detect poor connections under load.

Question 43: How long are hemodialysis patient treatment records typically required to be retained under federal regulations?

3 years only
1 year
A minimum of 6 years from the date of service, or longer if required by state law (Correct answer)
Indefinitely for all records

Correct answer: A minimum of 6 years from the date of service, or longer if required by state law

Federal CMS regulations and HIPAA generally require dialysis treatment records to be retained for at least 6 years, with some states mandating longer periods.

Question 44: Which record must be maintained for every hemodialysis machine to document its preventive maintenance, repairs, and disinfection history?

Patient treatment record
Water log only
Facility incident report
Machine maintenance log (Correct answer)

Correct answer: Machine maintenance log

A machine maintenance log documents all preventive maintenance, repairs, disinfections, and quality checks for each machine, providing a traceable service history for compliance and troubleshooting.

Question 45: When performing preventive maintenance on a hemodialysis machine, what electrical test measures the resistance between the equipment chassis and the ground pin of the power cord?

Dielectric strength test
Ground continuity test (Correct answer)
Leakage current test
Insulation resistance test

Correct answer: Ground continuity test

The ground continuity (protective earth resistance) test measures the resistance of the safety ground path from the equipment chassis to the power cord ground pin, which should typically be less than 0.1 ohm.

Question 46: Which of the following conditions is LEAST likely to be caused by uremia?

Edema (swelling) of the extremities
Urinary tract infection (Correct answer)
Anemia
Itching

Correct answer: Urinary tract infection

Uremia refers to the accumulation of waste products in the blood due to kidney failure. While uremia causes symptoms like itching, edema, and anemia, it does not directly cause urinary tract infections (UTIs). UTIs are typically caused by bacterial invasion of the urinary tract, often unrelated to the systemic effects of uremia.

Question 47: What is the recommended frequency for electrical safety testing of patient-connected hemodialysis equipment per AAMI standards?

Every 6 months (Correct answer)
Every 2 years
Monthly
Annually

Correct answer: Every 6 months

AAMI recommends electrical safety inspection and testing of patient-connected equipment at least every 6 months or per the manufacturer's recommendations.

Question 48: Failure to excrete beta2-microglobulin in patients with kidney failure predisposes the patient to:

pericarditis.
amyloidosis. (Correct answer)
neuropathy.
seizures.

Correct answer: amyloidosis.

Beta2-microglobulin is a small protein that is normally filtered and reabsorbed by healthy kidneys. In patients with kidney failure, it accumulates in the blood and can deposit in various tissues, forming amyloid fibrils. This deposition leads to dialysis-related amyloidosis, which can affect joints, bones, and other organs.

Question 49: What does ACT (Activated Clotting Time) measure in the context of hemodialysis anticoagulation monitoring?

The concentration of platelets in the post-filter blood sample
The rate at which heparin is cleared from the patient's bloodstream
The time for whole blood to clot, used to assess the adequacy of heparin anticoagulation (Correct answer)
The osmolarity of the dialysate adjusted for anticoagulant content

Correct answer: The time for whole blood to clot, used to assess the adequacy of heparin anticoagulation

ACT measures the time for whole blood to clot in the presence of an activating agent. Normal ACT is 90–130 seconds; therapeutic range during hemodialysis is typically 150–200 seconds. It guides heparin dose adjustments.

Question 50: Which NFPA standard specifically governs electrical safety requirements in health care facilities, including dialysis units?

NFPA 13
NFPA 70 (NEC)
NFPA 99 (Correct answer)
NFPA 101

Correct answer: NFPA 99

NFPA 99 (Health Care Facilities Code) establishes electrical safety requirements specific to health care environments, including patient care areas such as dialysis units.

Question 51: Which type of dialyzer membrane is most commonly used in modern hemodialysis?

Synthetic high-flux membrane (e.g., polysulfone) (Correct answer)
Cellulose acetate low-flux membrane
Cuprophane membrane
Natural latex membrane

Correct answer: Synthetic high-flux membrane (e.g., polysulfone)

High-flux synthetic membranes such as polysulfone are the current standard. They allow removal of larger middle molecules and have better biocompatibility compared to older cellulose-based membranes.

Question 52: Why must the hemodialysis machine alarm be checked if blood appears in the dialysate effluent?

It means the dialysate concentrate has changed color due to heparin interaction
It means the patient's hemoglobin is too high and needs to be evaluated
It is a normal finding when high-flux membranes are used
It indicates a blood leak through the dialyzer membrane, which can expose the patient to dialysate contaminants and cause blood loss (Correct answer)

Correct answer: It indicates a blood leak through the dialyzer membrane, which can expose the patient to dialysate contaminants and cause blood loss

Blood in the dialysate indicates a ruptured dialyzer membrane (blood leak). This is a serious emergency: blood is lost into the drain, the patient is exposed to dialysate, and treatment must be stopped immediately. The machine's blood leak detector alarm should have activated.

Question 53: Which hemodialysis schedule is likely to be most efficient?

Nocturnal home hemodialysis, 8 hours during sleep, 3 days a week
Short daily home hemodialysis, 2-3 hours a session, 5-7 days a week (Correct answer)
Conventional home hemodialysis
In-center hemodialysis, 3-4 hours a session, 3 days a week

Correct answer: Short daily home hemodialysis, 2-3 hours a session, 5-7 days a week

Short daily home hemodialysis is generally considered the most efficient schedule because it mimics natural kidney function more closely by providing more frequent, shorter treatments. This leads to better clearance of toxins, improved fluid management, and often better patient outcomes and quality of life compared to less frequent schedules.

Question 54: A patient on hemodialysis suddenly becomes unresponsive. After confirming unresponsiveness, the first action is:

Activate the emergency response system (call a code) and begin BLS/CPR assessment (Correct answer)
Administer a saline bolus for presumed hypotension before calling for help
Recheck the patient's blood pressure and wait 2 minutes to reassess
Stop the dialysis treatment and call the nephrologist's office for guidance

Correct answer: Activate the emergency response system (call a code) and begin BLS/CPR assessment

An unresponsive patient is a cardiac/medical emergency. The emergency response system must be activated immediately (call a code). While waiting for help, assess airway, breathing, and circulation, and begin CPR if indicated. Dialysis treatment is a secondary concern.

Question 55: Which contaminant in dialysis water is associated with aluminum bone disease and encephalopathy in dialysis patients?

Copper
Aluminum (Correct answer)
Fluoride
Nitrates

Correct answer: Aluminum

Aluminum contamination from municipal water or aluminum-containing flocculants accumulates in dialysis patients, causing aluminum bone disease (adynamic bone disorder) and dialysis encephalopathy (dementia-like syndrome).

Question 56: What is the primary goal of tracking machine-specific adverse event rates in a dialysis quality program?

To comply with insurance billing requirements for machine maintenance
To identify equipment-related trends that may indicate malfunction or calibration issues (Correct answer)
To rank technician performance based on the machines they operate
To determine which machines have the highest throughput for scheduling purposes

Correct answer: To identify equipment-related trends that may indicate malfunction or calibration issues

Tracking adverse events by machine allows the biomedical technician and clinical team to identify patterns suggesting equipment malfunction, miscalibration, or the need for preventive maintenance.

Question 57: Which type of electrical isolation transformer provides the safest power for patient-connected medical equipment in a dialysis unit?

Step-down transformer
Medical-grade isolation transformer (Correct answer)
Ferroresonant transformer
Autotransformer

Correct answer: Medical-grade isolation transformer

Medical-grade isolation transformers are specifically designed with low interwinding capacitance and meet NFPA 99 requirements, providing electrical isolation while minimizing hazard current in patient environments.

Question 58: Which site in the hemodialysis pathway has the highest positive pressure?

Blood entering the dialyzer fibers (Correct answer)
Blood in the venous return
Arterial blood in the afferent tubing
Blood leaving the dialyzer fibers

Correct answer: Blood entering the dialyzer fibers

In hemodialysis, blood is pumped from the patient's artery into the dialyzer. To effectively push blood through the narrow dialyzer fibers and facilitate filtration, the pressure is highest at the point where the blood first enters these fibers. This high positive pressure helps drive the filtration process across the membrane.

Question 59: What happens if dialysate calcium is set too high for a patient?

Metabolic acidosis
Hemolysis
Hypercalcemia, potentially causing cardiac arrhythmias, vascular calcification, and soft tissue deposits (Correct answer)
Hypocalcemia and tetany

Correct answer: Hypercalcemia, potentially causing cardiac arrhythmias, vascular calcification, and soft tissue deposits

Excess calcium transferred from dialysate to blood causes hypercalcemia, which can trigger arrhythmias, worsen vascular calcification, and cause soft tissue mineral deposits.

Question 60: The most common cause of chronic kidney disease in the United States is:

polycystic kidney disease.
hypertension.
diabetes. (Correct answer)
glomerulonephritis.

Correct answer: diabetes.

Diabetes is the leading cause of chronic kidney disease (CKD) in the United States, accounting for nearly half of all cases. High blood sugar levels over time damage the small blood vessels in the kidneys, impairing their ability to filter waste. This damage can progressively lead to kidney failure.

Question 61: What is the maximum allowable endotoxin level in hemodialysis product water per AAMI standards?

0.25 EU/mL (Correct answer)
1.0 EU/mL
0.001 EU/mL
5.0 EU/mL

Correct answer: 0.25 EU/mL

AAMI standards require endotoxin levels below 0.25 EU/mL in product water for standard hemodialysis. Ultrapure dialysate (used for on-line hemodiafiltration) requires <0.03 EU/mL. Action level is 0.125 EU/mL.

Question 62: Secondary hyperparathyroidism in CKD patients results primarily from:

Hypocalcemia and hyperphosphatemia triggering excess PTH secretion (Correct answer)
High vitamin D levels
Excess calcium supplementation
Parathyroid adenoma formation

Correct answer: Hypocalcemia and hyperphosphatemia triggering excess PTH secretion

Low calcium and high phosphate levels in CKD chronically stimulate the parathyroid glands, leading to hypertrophy and excess PTH secretion.

Question 63: What is the purpose of the venous pressure monitor in the hemodialysis blood circuit?

To detect access recirculation or obstruction in the return line (Correct answer)
To control the dialysate sodium concentration
To determine the heparin infusion rate
To measure the patient's systemic blood pressure

Correct answer: To detect access recirculation or obstruction in the return line

The venous pressure monitor measures pressure in the return (venous) line. Rising venous pressure may indicate a clot, needle malposition, or access stenosis; falling pressure may indicate needle dislodgement.

Question 64: For a patient at high bleeding risk (e.g., post-surgery or active GI bleed), which hemodialysis anticoagulation approach is preferred?

Use warfarin systemically the night before dialysis instead of heparin
Double the standard heparin dose to ensure the circuit does not clot
Switch the patient to peritoneal dialysis permanently
No-heparin (heparin-free) dialysis with frequent saline flushes to maintain circuit patency (Correct answer)

Correct answer: No-heparin (heparin-free) dialysis with frequent saline flushes to maintain circuit patency

For high-bleeding-risk patients, heparin-free dialysis uses saline flushes (50–100 mL every 15–30 minutes) to rinse the circuit and prevent clotting without systemic anticoagulation. High blood flow rates also reduce clotting tendency.

Question 65: Under CMS Conditions for Coverage, dialysis facilities must have a Quality Assessment and Performance Improvement (QAPI) program that includes:

Monthly equipment inspections without outcome tracking
Ongoing systematic monitoring of patient outcomes and care processes with documented improvement activities (Correct answer)
QAPI is optional for small facilities
Annual staff satisfaction surveys only

Correct answer: Ongoing systematic monitoring of patient outcomes and care processes with documented improvement activities

CMS requires ESRD facilities to operate a QAPI program with defined indicators, data collection, analysis, and documented improvement actions to continuously improve patient care quality.

Question 66: What is the purpose of a 5-micron sediment filter placed upstream of the carbon tanks?

To remove particulate matter that would clog or foul the carbon beds and RO membrane (Correct answer)
To remove bacteria and viruses from the feed water
To adjust pH of the incoming water to protect the RO membrane
To reduce total dissolved solids before the softener stage

Correct answer: To remove particulate matter that would clog or foul the carbon beds and RO membrane

The 5-micron (or 10-micron) sediment pre-filter is the first stage of water treatment. It removes sand, rust, and particulates that would foul the carbon beds and damage the RO membrane, extending system life and efficiency.

Question 67: Low-molecular-weight heparin (LMWH, e.g., enoxaparin) differs from unfractionated heparin in hemodialysis primarily because:

LMWH is safe for patients with heparin-induced thrombocytopenia (HIT)
LMWH has a shorter half-life than UFH and requires more frequent dosing
LMWH has a more predictable pharmacokinetic profile and longer half-life, allowing single-bolus dosing, but it is not reversible with protamine (Correct answer)
LMWH requires continuous infusion during dialysis like UFH

Correct answer: LMWH has a more predictable pharmacokinetic profile and longer half-life, allowing single-bolus dosing, but it is not reversible with protamine

LMWH can be given as a single pre-treatment bolus due to its predictable half-life. However, it is only partially reversible with protamine (approximately 60%) and accumulates in renal failure, making dose adjustment critical in dialysis patients.

Question 68: A biomedical technician measures 150 microamperes of chassis leakage current on a hemodialysis machine. What is the appropriate action?

Document the reading and continue normal operation
Reduce the voltage supply to lower leakage
Remove the machine from service immediately and tag it out of service (Correct answer)
Install an additional ground wire and return to service

Correct answer: Remove the machine from service immediately and tag it out of service

A chassis leakage current of 150 µA exceeds the AAMI limit of 100 µA, requiring the machine to be removed from service until the fault is identified and corrected.

Question 69: What is the effect of increasing dialysate bicarbonate concentration above normal physiologic levels?

Decreased conductivity alarm frequency
Reduced risk of hemolysis
Post-dialysis metabolic alkalosis, which can worsen respiratory depression and cause hypocalcemia-related symptoms (Correct answer)
Improved potassium removal

Correct answer: Post-dialysis metabolic alkalosis, which can worsen respiratory depression and cause hypocalcemia-related symptoms

Excessive bicarbonate transfer overcorrects acidosis, causing alkalosis that shifts calcium into the ionized-to-bound ratio, triggers tetany, and may suppress respiratory drive.

Question 70: Why is glucose often added to hemodialysis dialysate?

To increase dialysate osmolality for ultrafiltration
To inhibit bacterial growth
To prevent hypoglycemia during treatment and reduce glucose loss across the membrane (Correct answer)
To serve as an energy source for the dialyzer membrane

Correct answer: To prevent hypoglycemia during treatment and reduce glucose loss across the membrane

Adding glucose (typically 100–200 mg/dL) to dialysate helps prevent intradialytic hypoglycemia and reduces net glucose loss, particularly in diabetic patients.

Question 71: What information must be labeled on a reprocessed dialyzer?

The dialyzer serial number and manufacturing date only
The technician's name and the machine it will be used on
Patient name/ID, number of previous uses, date of last reprocessing, and disinfectant used (Correct answer)
Only the patient's name and room number

Correct answer: Patient name/ID, number of previous uses, date of last reprocessing, and disinfectant used

AAMI and CMS standards require reprocessed dialyzer labels to include patient identification, number of prior uses, date/time of reprocessing, and the disinfectant used. This ensures the correct dialyzer is used for the correct patient and use limits are tracked.

Question 72: Why is magnesium included in the acid concentrate for hemodialysis dialysate?

To prevent bacterial growth
To improve dialyzer membrane performance
To increase dialysate conductivity
To replace magnesium removed during dialysis and prevent hypomagnesemia, which can cause cardiac arrhythmias and neuromuscular irritability (Correct answer)

Correct answer: To replace magnesium removed during dialysis and prevent hypomagnesemia, which can cause cardiac arrhythmias and neuromuscular irritability

Dialysis removes magnesium; including a physiologic level in dialysate replaces losses and maintains normal serum magnesium to prevent cardiac and neuromuscular complications.

Question 73: In quality assurance, what does a 'sentinel event' refer to in a hemodialysis unit?

A routine equipment failure that is logged for end-of-month review
An unexpected occurrence involving death or serious physical harm that requires immediate investigation (Correct answer)
A minor patient complaint about treatment discomfort
A scheduled inspection by a regulatory agency

Correct answer: An unexpected occurrence involving death or serious physical harm that requires immediate investigation

A sentinel event is an unexpected event resulting in death or serious harm. In dialysis, examples include air embolism or wrong-patient dialysis. These require root-cause analysis and immediate corrective action.

Question 74: A patient's prescribed heparin dose is 2,000 units bolus followed by 1,000 units/hour. The session runs 4 hours. What is the total heparin administered (assuming the infusion stops 30 minutes before the end)?

2,000 units
5,500 units (Correct answer)
6,000 units
4,000 units

Correct answer: 5,500 units

Bolus: 2,000 units. Infusion runs 3.5 hours (stopped 30 min early): 1,000 × 3.5 = 3,500 units. Total = 2,000 + 3,500 = 5,500 units.

Question 75: A dialysis facility's water treatment log must include which of the following entries?

Machine serial numbers only
Patient names treated that day
Concentrate lot numbers only
Date, time, name of person performing test, water quality parameters tested, and results compared to acceptable ranges (Correct answer)

Correct answer: Date, time, name of person performing test, water quality parameters tested, and results compared to acceptable ranges

Water logs must document the who, when, what, and results of all water quality checks to demonstrate ongoing compliance with AAMI standards and enable trend analysis.

Question 76: The dialysate temperature is typically set between:

25–30°C
38–41°C
32–34°C for all patients
35–37°C to match or slightly approximate body temperature (Correct answer)

Correct answer: 35–37°C to match or slightly approximate body temperature

Dialysate temperature of 35–37°C optimizes patient comfort and hemodynamic stability, with cooler temperatures sometimes used to reduce intradialytic hypotension.

Question 77: What percentage of transplanted kidneys are functional 1 year after transplantation?

50%
90% (Correct answer)
30%
70%

Correct answer: 90%

Kidney transplantation has a high success rate, with approximately 90% of transplanted kidneys from deceased donors and an even higher percentage from living donors remaining functional one year post-transplantation. This high success rate makes transplantation a preferred treatment option for end-stage kidney disease.

Question 78: A blood leak alarm activates during treatment. What is the correct first response by the biomed technician verifying the alarm?

Increase blood flow rate
Replace the dialysate proportioning pump
Silence the alarm and continue treatment
Inspect the dialysate outflow for pink or red discoloration (Correct answer)

Correct answer: Inspect the dialysate outflow for pink or red discoloration

Visual inspection of the dialysate effluent for discoloration confirms whether a true blood leak has occurred through the membrane.

Question 79: How frequently should dialysis station surfaces be disinfected between patients?

Once daily at the end of the shift
Only when visibly soiled with blood
After every patient treatment, before the next patient occupies the station (Correct answer)
Weekly deep cleaning only

Correct answer: After every patient treatment, before the next patient occupies the station

All dialysis station surfaces must be disinfected between each patient to prevent transmission of bloodborne pathogens and other organisms.

Question 80: Which organization publishes the primary infection prevention recommendations specifically for hemodialysis settings in the United States?

CMS (Centers for Medicare & Medicaid Services) through ESRD conditions of coverage
AAMI (Association for the Advancement of Medical Instrumentation) through dialyzer standards
The CDC (Centers for Disease Control and Prevention) through its Hemodialysis Infection Prevention Collaborative (Correct answer)
The FDA (Food and Drug Administration) through medical device guidelines

Correct answer: The CDC (Centers for Disease Control and Prevention) through its Hemodialysis Infection Prevention Collaborative

The CDC's Hemodialysis Infection Prevention Collaborative and its Core Interventions for Hemodialysis Bloodstream Infection Prevention provide the primary infection control guidance for dialysis units in the US. CMS enforces compliance through ESRD conditions.

Question 81: What happens to the water softener resin during regeneration, and what chemical is used?

Distilled water backwashes the resin to remove trapped particulates
Saturated sodium chloride (brine) solution flushes the resin, replacing accumulated calcium and magnesium with sodium ions (Correct answer)
Hydrochloric acid dissolves the resin and it must be replaced
Peracetic acid disinfects the resin to remove bacterial biofilm

Correct answer: Saturated sodium chloride (brine) solution flushes the resin, replacing accumulated calcium and magnesium with sodium ions

Water softener regeneration uses concentrated brine (NaCl solution). The high sodium concentration displaces calcium and magnesium ions from the resin exchange sites via mass action, restoring the resin's softening capacity.

Question 82: Which vaccine is specifically recommended for all susceptible hemodialysis staff and patients due to the high risk of HBV transmission in dialysis units?

Hepatitis B vaccine series with post-vaccination serologic testing to confirm immunity (anti-HBs ≥10 mIU/mL) (Correct answer)
Influenza vaccine only, since HBV immunity is presumed in dialysis staff
Hepatitis A vaccine since it is more easily transmitted in healthcare settings
No vaccine is available; infection control practices are the only protection

Correct answer: Hepatitis B vaccine series with post-vaccination serologic testing to confirm immunity (anti-HBs ≥10 mIU/mL)

HBV vaccination is mandatory for dialysis staff and strongly recommended for patients. Post-vaccination testing confirms protective antibody levels (anti-HBs ≥10 mIU/mL). Dialysis patients may have a blunted immune response and require higher-dose or additional booster doses.

Question 83: What is the purpose of the CMS ESRD Quality Incentive Program (QIP)?

To regulate water treatment equipment manufacturers
To certify biomed technicians nationally
To set staffing ratios for nursing staff
To link Medicare payment to dialysis facility performance on quality measures, with payment reductions for poor performance (Correct answer)

Correct answer: To link Medicare payment to dialysis facility performance on quality measures, with payment reductions for poor performance

The QIP uses a scoring system to evaluate facility performance on clinical, safety, and reporting measures, reducing Medicare payments for facilities that score below the performance threshold.

Question 84: What is 'microshock' hazard in hemodialysis patients particularly relevant for those with central venous catheters?

Ground fault currents exceeding 5 mA
High-voltage discharges from capacitors
Currents of 1–100 mA applied externally to the body
Currents as low as 10–20 microamperes applied directly to the heart (Correct answer)

Correct answer: Currents as low as 10–20 microamperes applied directly to the heart

Microshock involves currents as low as 10–20 microamperes that bypass skin resistance via internal pathways (e.g., central catheters) and can induce ventricular fibrillation.

Question 85: During an emergency fire evacuation from a dialysis unit, patients connected to machines should be:

Left connected to machines since disconnection causes more risk than evacuation with equipment
Returned their blood if time allows, disconnected from machines, and evacuated per the facility's emergency plan (Correct answer)
Told to remain in their chairs while staff evacuates non-ambulatory patients first
Disconnected immediately by cutting the blood lines regardless of circuit status

Correct answer: Returned their blood if time allows, disconnected from machines, and evacuated per the facility's emergency plan

Facility emergency evacuation plans prioritize returning blood to minimize patient blood loss, then safe disconnection before evacuation. If immediate danger prevents return of blood, lines are clamped and the patient disconnected. Patient mobility level determines evacuation order.

Question 86: Which ion in dialysate is primarily responsible for controlling dialysate conductivity?

Potassium
Bicarbonate
Sodium (Correct answer)
Calcium

Correct answer: Sodium

Sodium is present in the highest concentration in dialysate and contributes most to overall ionic conductivity, making it the primary determinant of conductivity readings.

Question 87: A dialysis machine's reverse osmosis system fails mid-shift. What is the correct course of action?

Switch to tap water temporarily until the RO is repaired
Safely discontinue all treatments using that water supply and notify the biomedical technician and facility manager (Correct answer)
Continue treatments on machines already running since they are already connected
Dilute the dialysate 1:1 with saline to reduce contaminant concentration

Correct answer: Safely discontinue all treatments using that water supply and notify the biomedical technician and facility manager

RO failure means purified water is no longer available. All treatments dependent on that water supply must be safely discontinued. Using tap water or non-purified water for dialysate preparation is potentially fatal due to chloramine and contaminant exposure.

Question 88: Which dialysis modality is specifically designed for patients with acute kidney injury in an ICU setting due to its slow, continuous fluid removal?

Intermittent Hemodialysis (IHD)
Peritoneal Dialysis (PD)
Continuous Renal Replacement Therapy (CRRT) (Correct answer)
Sustained Low Efficiency Dialysis (SLED)

Correct answer: Continuous Renal Replacement Therapy (CRRT)

CRRT is used in hemodynamically unstable ICU patients. It runs 24 hours/day and removes fluid slowly, minimizing cardiovascular stress compared to conventional intermittent hemodialysis.

Question 89: Sodium profiling during hemodialysis involves:

Varying the dialysate sodium concentration during treatment to improve hemodynamic stability and reduce intradialytic symptoms (Correct answer)
Measuring serum sodium every 30 minutes
Restricting sodium intake on dialysis days
Using a fixed low-sodium dialysate throughout treatment

Correct answer: Varying the dialysate sodium concentration during treatment to improve hemodynamic stability and reduce intradialytic symptoms

Sodium profiling gradually decreases dialysate sodium from higher to lower levels during treatment, helping preserve osmolality early and reducing cramping and hypotension.

Question 90: What is the primary justification for dialyzer reuse programs in hemodialysis?

Reuse is required by CMS as a cost-saving measure for ESRD programs
Cost reduction and potential improvement in biocompatibility due to protein coating of the membrane reducing first-use syndrome (Correct answer)
Reused dialyzers have a smaller priming volume, reducing patient blood loss
Reused dialyzers provide higher clearance than new dialyzers

Correct answer: Cost reduction and potential improvement in biocompatibility due to protein coating of the membrane reducing first-use syndrome

Dialyzer reuse reduces facility costs and may reduce first-use syndrome. Protein deposition on the membrane during first use creates a more biocompatible surface for subsequent uses. However, reuse programs require strict protocols to maintain safety and efficacy.

Question 91: During hemodialysis, why is the dialysate run in a countercurrent direction to blood flow?

To maintain the maximum concentration gradient along the entire length of the dialyzer, improving efficiency (Correct answer)
To allow ultrafiltration to occur in both directions
To reduce the risk of air entering the blood circuit
To prevent clotting in the blood compartment

Correct answer: To maintain the maximum concentration gradient along the entire length of the dialyzer, improving efficiency

Countercurrent flow ensures that blood and dialysate always have a concentration difference along the entire membrane, maximizing diffusion efficiency throughout the dialyzer rather than reaching equilibrium early.

Question 92: In the context of hemodialysis equipment, what does 'macroshock' refer to?

Static electricity buildup on equipment
Current above 1 mA applied to the skin surface (Correct answer)
Current applied directly to the heart via a catheter
Electrical discharge from a capacitor

Correct answer: Current above 1 mA applied to the skin surface

Macroshock refers to currents above approximately 1 mA that are perceptible at the skin surface and can cause muscle contraction, respiratory arrest, or ventricular fibrillation at higher levels.

Question 93: Hepatitis B virus (HBV) poses a special risk in dialysis units because:

All dialysis patients are immunocompromised and cannot be vaccinated against HBV
HBV requires only casual contact for transmission and spreads rapidly in shared spaces
HBV is transmitted through the dialysate and cannot be filtered by standard dialyzer membranes
HBV can survive on surfaces for up to 7 days and is highly infectious, making environmental contamination a significant transmission route (Correct answer)

Correct answer: HBV can survive on surfaces for up to 7 days and is highly infectious, making environmental contamination a significant transmission route

HBV is an extremely hardy virus that survives on contaminated surfaces for up to 7 days at room temperature. In dialysis units, blood contamination of surfaces, equipment, and supplies makes environmental cleaning critical. HBV-positive patients must be treated in separate rooms/machines.

Question 94: During a hemodialysis treatment, a patient reports chest pain and shortness of breath. The technician should:

Stop the treatment immediately, call for emergency assistance, and monitor the patient (Correct answer)
Increase the dialysate temperature to improve circulation
Slow the blood pump speed and continue treatment while observing
Reassure the patient and complete the session before notifying the charge nurse

Correct answer: Stop the treatment immediately, call for emergency assistance, and monitor the patient

Chest pain and shortness of breath are potential signs of a cardiac event or air embolism. Treatment must be stopped immediately, emergency help called, and the patient closely monitored as per emergency protocols.

Question 95: A hollow-fiber dialyzer contains thousands of hollow fibers through which blood flows. What is the primary advantage of this design?

It enables reuse of the dialyzer without disinfection
It eliminates the need for anticoagulation during dialysis
It provides a large surface area for diffusion in a compact device (Correct answer)
It allows for higher dialysate temperatures

Correct answer: It provides a large surface area for diffusion in a compact device

Hollow-fiber dialyzers pack thousands of tiny capillary fibers into a small cartridge, providing a surface area of 0.8–2.1 m² for solute and fluid exchange. This design optimizes clearance efficiency in a small footprint.

Question 96: How is the heparin pump on a hemodialysis machine typically primed before treatment?

Flushed with saline until heparin appears at the needle tip (Correct answer)
Run at maximum rate for 2 minutes
Filled with dialysate
Pre-filled by the manufacturer

Correct answer: Flushed with saline until heparin appears at the needle tip

The heparin infusion line is primed with saline and then heparin is advanced to the needle tip to remove air and ensure accurate dosing from the start.

Question 97: Which class of medical electrical equipment relies solely on basic insulation for patient protection with NO protective earth connection?

Class II (Correct answer)
Class III
Class I
Type CF

Correct answer: Class II

Class II equipment (double-insulated) uses reinforced or double insulation rather than a protective earth connection to protect against electric shock.

Question 98: How frequently must hemodialysis facilities conduct water quality testing for bacteria and endotoxins per AAMI recommendations?

Annually
Monthly for bacteria; monthly for endotoxins, with cultures drawn from multiple points in the water distribution system (Correct answer)
Only when a patient has a pyrogenic reaction
Weekly for conductivity; annually for bacteria

Correct answer: Monthly for bacteria; monthly for endotoxins, with cultures drawn from multiple points in the water distribution system

AAMI recommends monthly microbiological cultures and endotoxin testing at multiple distribution points to detect contamination trends before patients are harmed.

Question 99: What is the function of a ground fault circuit interrupter (GFCI) in a hemodialysis clinical environment?

It isolates patient circuits from building power
It interrupts power when current imbalance between hot and neutral exceeds ~5 mA (Correct answer)
It regulates voltage to dialysis machines
It monitors dialysate conductivity

Correct answer: It interrupts power when current imbalance between hot and neutral exceeds ~5 mA

A GFCI detects a current difference of approximately 4–6 mA between the hot and neutral conductors, indicating current leaking to ground, and interrupts the circuit within milliseconds.

Question 100: Which solute transport mechanism in hemodialysis relies on a concentration gradient between blood and dialysate?

Convection
Diffusion (Correct answer)
Ultrafiltration
Osmosis

Correct answer: Diffusion

Diffusion is the primary mechanism of solute removal in hemodialysis. Solutes move from an area of higher concentration (blood) to lower concentration (dialysate) across the semipermeable membrane.

Question 101: Which component in the water treatment system is specifically designed to remove chlorine and chloramines from municipal water?

Sediment pre-filters (5-micron)
Activated carbon adsorption tanks (Correct answer)
Ultraviolet sterilization lamps
Water softeners (cation exchange resin)

Correct answer: Activated carbon adsorption tanks

Activated carbon tanks adsorb chlorine and chloramine through chemical bonding. Two carbon tanks in series are required, with testing between them to verify complete removal before water reaches the RO membrane.

Question 102: What is the primary safety risk if chloramines are not adequately removed from dialysis water?

Elevated dialysate conductivity only
Decreased solute clearance
Hemolytic anemia from chloramine crossing the dialyzer membrane and destroying red blood cells (Correct answer)
Access site infection

Correct answer: Hemolytic anemia from chloramine crossing the dialyzer membrane and destroying red blood cells

Chloramines pass freely through dialyzer membranes, entering the bloodstream and oxidizing red blood cell membranes, causing hemolysis and potentially fatal anemia.

Question 103: Heparin resistance in a dialysis patient is most commonly associated with:

Elevated platelet counts above 500,000/µL
Antithrombin III (AT-III) deficiency, since heparin requires AT-III to exert its anticoagulant effect (Correct answer)
Chronic heparin exposure reducing receptor sensitivity
Vitamin K excess from dietary sources

Correct answer: Antithrombin III (AT-III) deficiency, since heparin requires AT-III to exert its anticoagulant effect

Heparin binds and activates antithrombin III, which then inhibits thrombin and Factor Xa. AT-III deficiency (from nephrotic syndrome, liver disease, or hereditary causes) renders heparin ineffective. Treatment includes AT-III supplementation or alternative anticoagulants.

Question 104: If a dialysis machine's temperature sensor fails during treatment, what is the primary patient risk?

Hypoglycemia
Air embolism
Hemolysis from overheated dialysate (Correct answer)
Metabolic alkalosis

Correct answer: Hemolysis from overheated dialysate

Dialysate delivered above approximately 42°C can cause thermal hemolysis, destroying red blood cells and releasing potassium with potentially fatal consequences.

Question 105: What is the maximum allowable leakage current for patient-connected medical equipment according to AAMI/IEC standards?

50 microamperes
100 microamperes (Correct answer)
10 microamperes
500 microamperes

Correct answer: 100 microamperes

AAMI/IEC 60601-1 sets 100 microamperes (0.1 mA) as the maximum allowable patient leakage current for Type B applied parts under normal conditions.

Question 106: Why is anticoagulation necessary during hemodialysis?

It is required to maintain the patient's dry weight during treatment
Anticoagulation prevents the dialyzer membrane from rejecting blood cells
Blood contact with the extracorporeal circuit activates the coagulation cascade, which would clot the dialyzer and tubing (Correct answer)
It prevents dialysate from entering the bloodstream through the membrane

Correct answer: Blood contact with the extracorporeal circuit activates the coagulation cascade, which would clot the dialyzer and tubing

The extracorporeal circuit (tubing, dialyzer) is a foreign surface that activates platelets and clotting factors. Without anticoagulation, the system would clot within minutes, terminating treatment and potentially causing blood loss.

Question 107: What is the purpose of a quality assurance water culture in a hemodialysis unit?

To detect bacterial contamination levels in the water used to prepare dialysate (Correct answer)
To confirm that chloramine levels are within acceptable pH limits
To measure the chemical composition of the dialysate concentrate
To verify the proper functioning of the reverse osmosis membrane pressure

Correct answer: To detect bacterial contamination levels in the water used to prepare dialysate

Monthly water cultures detect bacterial counts in product water and dialysate. AAMI standards require <100 CFU/mL for product water and <200 CFU/mL for dialysate to ensure patient safety.

Question 108: What is the most commonly used anticoagulant in hemodialysis?

Rivaroxaban (Xarelto)
Warfarin (Coumadin)
Aspirin
Unfractionated heparin (UFH) (Correct answer)

Correct answer: Unfractionated heparin (UFH)

Unfractionated heparin is the standard anticoagulant for hemodialysis. It acts rapidly, has a short half-life (1–2 hours), is reversible with protamine sulfate, and is cost-effective. It is administered as a bolus at initiation and continuous infusion during treatment.

Question 109: According to AAMI/ANSI standards, what is the maximum allowable bacterial count (CFU/mL) in hemodialysis product water?

1,000 CFU/mL
10 CFU/mL
500 CFU/mL
100 CFU/mL (Correct answer)

Correct answer: 100 CFU/mL

AAMI standards (ANSI/AAMI RD52) specify a maximum of 100 CFU/mL for product water. The action level is 50 CFU/mL. Exceeding these levels requires immediate investigation and corrective action.

Question 110: What is the primary purpose of a line isolation monitor (LIM) in a dialysis unit?

To regulate current flow to the blood pump
To monitor water quality in the dialysate circuit
To detect loss of isolation in an isolated power system (Correct answer)
To measure voltage output of dialysis machines

Correct answer: To detect loss of isolation in an isolated power system

A line isolation monitor continuously measures the impedance between the isolated power lines and ground, alarming when the fault hazard current exceeds safe limits (typically 2 mA or 5 mA).

Question 111: Why must HBV-positive hemodialysis patients be treated in a separate room or area with dedicated machines?

Because HBV is highly stable in the environment and routine disinfection may be insufficient to prevent transmission via shared equipment or surfaces (Correct answer)
Because HBV-positive patients are more likely to have access complications requiring isolation for monitoring
Because HBV-positive patients require a different dialysate formulation
Because CMS regulations prohibit HBV-positive patients from being in the same room as other patients

Correct answer: Because HBV is highly stable in the environment and routine disinfection may be insufficient to prevent transmission via shared equipment or surfaces

HBV's environmental stability (7 days on surfaces) and high infectivity (10,000 virions per mL of blood) make it transmissible even with standard disinfection. Dedicated machines and separation prevent the cluster outbreaks that occurred in dialysis units before these policies were established.

Question 112: A patient on hemodialysis is known to have heparin-induced thrombocytopenia (HIT). Which anticoagulant is safe to use as an alternative?

Citrate only in peritoneal dialysis patients
Low-molecular-weight heparin (enoxaparin)
Protamine sulfate
Argatroban or lepirudin (direct thrombin inhibitors) (Correct answer)

Correct answer: Argatroban or lepirudin (direct thrombin inhibitors)

HIT is caused by antibodies against heparin-platelet factor 4 complexes. ALL heparin products (including LMWH) are contraindicated. Direct thrombin inhibitors like argatroban do not cross-react with HIT antibodies and are the safe alternative.

Question 113: What is the typical timing for 'heparin reversal' at the end of a hemodialysis session?

Heparin is continued until the needles are removed, then stopped
Heparin infusion is stopped 30–60 minutes before the end of treatment to allow clotting to normalize and reduce post-needle-removal bleeding (Correct answer)
Protamine sulfate is administered as heparin infusion continues until the last minute
Heparin reversal is not performed; the anticoagulant effect wears off on its own over 24 hours

Correct answer: Heparin infusion is stopped 30–60 minutes before the end of treatment to allow clotting to normalize and reduce post-needle-removal bleeding

Stopping heparin 30–60 minutes before treatment ends (tight heparin protocol) allows the anticoagulant effect to diminish. This reduces post-cannulation site bleeding while maintaining adequate anticoagulation for most of the session.

Question 114: Which dialysate electrolyte change can precipitate dangerous cardiac arrhythmias, particularly in digitalized or hypokalemic patients?

Mild decrease in dialysate bicarbonate
Slight increase in dialysate sodium
Low dialysate calcium combined with normal potassium
Rapid reduction of serum potassium by using very low (0–1 mEq/L) dialysate potassium (Correct answer)

Correct answer: Rapid reduction of serum potassium by using very low (0–1 mEq/L) dialysate potassium

Aggressive potassium removal with very low dialysate potassium creates a rapid intradialytic fall in serum potassium, which is a major trigger for ventricular arrhythmias.

Question 115: During a power failure in a dialysis unit, which component of the electrical system is designed to provide immediate backup power to hemodialysis machines without interruption?

Isolation transformer
Generator transfer switch
Uninterruptible power supply (UPS) (Correct answer)
Line isolation monitor

Correct answer: Uninterruptible power supply (UPS)

A UPS (uninterruptible power supply) provides instantaneous battery-backed power during outages, while generators have a transfer delay of several seconds that could interrupt treatment.

Question 116: What is the role of the priming step in anticoagulation preparation before connecting a patient to the hemodialysis circuit?

Priming removes endotoxins from the dialyzer by flushing with heparinized saline
Priming tests the blood pump speed before the patient is connected
Priming with heparinized saline coats the circuit surfaces, reducing thrombogenic activation when blood contacts the lines (Correct answer)
Priming equilibrates dialysate concentration within the dialyzer fiber bundle

Correct answer: Priming with heparinized saline coats the circuit surfaces, reducing thrombogenic activation when blood contacts the lines

Priming the extracorporeal circuit with heparinized saline pre-coats the tubing and dialyzer with heparin, reducing the thrombogenic surface. It also removes manufacturing residuals and trapped air from the circuit.

Question 117: Which dialysis machine component separates the concentrate mixture from the patient's blood circuit?

Blood leak detector
Proportioning pump
Deaeration chamber
Dialyzer membrane (Correct answer)

Correct answer: Dialyzer membrane

The semi-permeable dialyzer membrane separates the blood and dialysate compartments, allowing solute diffusion while preventing direct fluid mixing.

Question 118: Which of the following is the most critical immediate action when a patient on hemodialysis develops sudden hypotension?

Place the patient in the Trendelenburg position and administer a normal saline bolus (Correct answer)
Increase the ultrafiltration rate to remove excess fluid faster
Administer a vasopressor medication without notifying the nurse
Disconnect the patient from the dialysis circuit immediately

Correct answer: Place the patient in the Trendelenburg position and administer a normal saline bolus

Sudden hypotension during hemodialysis is managed by placing the patient in Trendelenburg position (legs elevated) and administering a normal saline bolus to restore circulating volume. Increasing ultrafiltration would worsen hypotension.

Question 119: What causes dialysis disequilibrium syndrome?

Contaminated dialysate entering the bloodstream
Excessive removal of potassium leading to cardiac arrhythmia
Air embolism from the venous blood circuit
Rapid removal of urea causes an osmotic gradient that draws water into brain cells, causing cerebral edema (Correct answer)

Correct answer: Rapid removal of urea causes an osmotic gradient that draws water into brain cells, causing cerebral edema

Dialysis disequilibrium syndrome occurs when BUN drops rapidly, creating an osmotic gradient. Urea acts as an idiogenic osmole in brain cells, drawing water in and causing cerebral edema with symptoms of nausea, headache, and seizure.

Question 120: Which bloodborne pathogen is MOST efficiently transmitted by needlestick injury in the hemodialysis setting?

Hepatitis B virus (HBV) (Correct answer)
Hepatitis C virus (HCV)
HIV
Cytomegalovirus (CMV)

Correct answer: Hepatitis B virus (HBV)

HBV has the highest transmission risk per needlestick exposure (up to 30%), far exceeding HCV (~3%) and HIV (~0.3%).

Question 121: Which organization accredits dialysis facilities in the United States and is recognized as an alternative to direct CMS surveys?

The Joint Commission (TJC) or DNV GL Healthcare, which have CMS-deemed status (Correct answer)
The American Nephrology Nurses Association (ANNA)
OSHA
AAMI

Correct answer: The Joint Commission (TJC) or DNV GL Healthcare, which have CMS-deemed status

The Joint Commission and DNV GL Healthcare hold CMS-deemed status for dialysis facilities, meaning their accreditation surveys satisfy the CMS Conditions for Coverage requirement.

Question 122: The arterial pressure alarm (low limit) on a hemodialysis machine is triggered. What does this most commonly indicate?

Inadequate blood flow from the access, such as needle malposition, access stenosis, or hypotension (Correct answer)
The arterial blood pump is running too fast for the dialyzer
Air bubbles in the arterial drip chamber
Too much heparin causing blood to flow too freely through the circuit

Correct answer: Inadequate blood flow from the access, such as needle malposition, access stenosis, or hypotension

Low arterial pressure indicates the blood pump is not getting enough blood from the access. This may be due to needle malposition, access dysfunction, patient hypotension, or the patient rolling onto the access. It must be corrected to maintain adequate treatment delivery.

Question 123: Which document must be verified before initiating a dialysis treatment to ensure patient safety?

The prior month's billing statement
The technician's certification renewal date
The physician's dialysis prescription order (Correct answer)
The patient's insurance authorization form

Correct answer: The physician's dialysis prescription order

Verifying the physician's dialysis prescription is a mandatory safety step before initiating treatment. The prescription specifies treatment time, blood flow rate, dialysate composition, and dry weight goals.

Question 124: Standard precautions in hemodialysis require that blood and body fluids from ALL patients be treated as:

Infectious only during active bleeding
Potentially infectious regardless of diagnosis or perceived risk (Correct answer)
Infectious only if the patient has a known bloodborne disease
Non-infectious if the patient tested negative last month

Correct answer: Potentially infectious regardless of diagnosis or perceived risk

Standard precautions treat all blood and body fluids as potentially infectious to protect staff and patients regardless of known infection status.

Question 125: What is the primary biomedical engineering reason for using isolated power systems rather than standard grounded power in dialysis patient care areas?

To provide higher voltage for dialysis machines
To reduce energy consumption of equipment
To allow use of three-phase electrical loads
To prevent a single ground fault from causing power interruption or patient electrocution (Correct answer)

Correct answer: To prevent a single ground fault from causing power interruption or patient electrocution

In an isolated power system, a single line-to-ground fault does not complete a circuit, preventing shock to a grounded patient and allowing continuous operation while the fault is located.

Question 126: What is the purpose of bicarbonate in hemodialysis dialysate?

To prevent bacterial growth in the dialysate
To remove excess potassium
To correct metabolic acidosis by providing a buffer that crosses into the patient's blood (Correct answer)
To lower dialysate conductivity

Correct answer: To correct metabolic acidosis by providing a buffer that crosses into the patient's blood

Bicarbonate in dialysate diffuses across the membrane into the blood, replacing bicarbonate lost to ESRD-associated metabolic acidosis and restoring acid-base balance.

Question 127: A technician notices the bicarbonate concentrate port has crystalline buildup. What is the correct corrective action?

Clean the port with warm water per manufacturer protocol to remove bicarbonate precipitate (Correct answer)
Replace the entire proportioning system
Use a stronger acid concentrate to dissolve buildup
Ignore it if conductivity readings are normal

Correct answer: Clean the port with warm water per manufacturer protocol to remove bicarbonate precipitate

Bicarbonate precipitate should be removed by cleaning the port with warm water as directed by the manufacturer, since buildup can affect flow and contaminate the system.

Question 128: AAMI (Association for the Advancement of Medical Instrumentation) standards most directly govern which aspect of dialysis facility operations?

Patient staffing ratios
Water treatment and dialysate quality standards (Correct answer)
Physician prescribing authority
Billing and coding practices

Correct answer: Water treatment and dialysate quality standards

AAMI publishes the technical standards (e.g., ANSI/AAMI RD52) for hemodialysis water and dialysate quality that facilities are expected to meet.

Question 129: What action should a dialysis technician take if a patient's access needle is accidentally dislodged during treatment?

Elevate the affected limb and continue treating with the remaining connected needle
Apply a tourniquet above the access site and continue dialysis through the remaining needle
Apply immediate firm pressure to the puncture site, stop the blood pump, and call for emergency assistance (Correct answer)
Quickly reinsert the needle and resume treatment to minimize blood loss

Correct answer: Apply immediate firm pressure to the puncture site, stop the blood pump, and call for emergency assistance

Needle dislodgement can cause rapid, life-threatening blood loss. Immediate firm pressure must be applied, the blood pump stopped, and emergency help summoned. The volume of blood lost must be estimated and documented.

Question 130: After using heat disinfection on a dialysis machine, the technician must verify the machine is safe for the next patient by:

Testing the dialysate conductivity only
Completing the cool-down rinse cycle and confirming readiness indicators before connecting the patient (Correct answer)
Waiting 30 minutes with no further verification
Replacing all blood tubing

Correct answer: Completing the cool-down rinse cycle and confirming readiness indicators before connecting the patient

Heat disinfection must be followed by a complete rinse and cool-down cycle, and the machine must signal readiness before patient connection to ensure safe dialysate temperature and no residual disinfectant.

Question 131: What chemical is most commonly used for disinfecting the internal fluid pathways of a hemodialysis machine?

Alcohol-based solution
Glutaraldehyde
Quaternary ammonium compounds
Peracetic acid or bleach (sodium hypochlorite) per manufacturer protocol (Correct answer)

Correct answer: Peracetic acid or bleach (sodium hypochlorite) per manufacturer protocol

Peracetic acid and sodium hypochlorite are the most widely used chemical disinfectants for hemodialysis machine internal pathways due to their broad-spectrum efficacy and compatibility.

Question 132: What concentration of dialysate potassium is typically used for patients with pre-dialysis serum potassium above 6.0 mEq/L?

3 mEq/L as a standard default
0 mEq/L in all hyperkalemic patients regardless of cardiac status
4 mEq/L to match plasma levels
1–2 mEq/L to enhance potassium removal while monitoring closely for arrhythmias (Correct answer)

Correct answer: 1–2 mEq/L to enhance potassium removal while monitoring closely for arrhythmias

A low dialysate potassium of 1–2 mEq/L maximizes potassium removal in hyperkalemic patients, but cardiac monitoring is essential because the steep gradient increases arrhythmia risk.

Question 133: What is the minimum recommended spKt/V per treatment for thrice-weekly hemodialysis per KDOQI guidelines?

1.0
1.4
0.8
1.2 (Correct answer)

Correct answer: 1.2

KDOQI guidelines recommend a minimum single-pool Kt/V (spKt/V) of 1.2 per treatment for patients on thrice-weekly hemodialysis.

Question 134: What does a failing 'pressure test' on a reprocessed dialyzer most commonly indicate?

The TCV has dropped below acceptable limits
The dialyzer housing is cracked and needs replacement
The disinfectant has degraded and is no longer effective
Ruptured hollow fibers in the dialyzer bundle, which would allow blood and dialysate to mix during treatment (Correct answer)

Correct answer: Ruptured hollow fibers in the dialyzer bundle, which would allow blood and dialysate to mix during treatment

The pressure test detects broken hollow fibers. Ruptured fibers create a pathway for blood-dialysate mixing, causing a blood leak during treatment. This is a patient safety issue (blood loss, dialysate exposure) and the dialyzer must be immediately discarded.

Question 135: Which type of grounding system is specifically required for patient care areas in dialysis units to minimize electrical hazards?

Isolated power system (Correct answer)
Equipotential grounding system
Standard two-wire grounding
Double-insulated system

Correct answer: Isolated power system

Isolated power systems (IPS) are required in critical care patient areas including dialysis to prevent ground fault currents from passing through the patient.

Question 136: Why must acid and bicarbonate concentrates be kept separate until just before mixing in the proportioning system?

Premixed solution becomes too acidic
The mixture is explosive
Regulations require separate storage only
Premixing causes bicarbonate to precipitate as calcium and magnesium carbonate (Correct answer)

Correct answer: Premixing causes bicarbonate to precipitate as calcium and magnesium carbonate

When acid and bicarbonate concentrates are combined early, calcium and magnesium ions react with bicarbonate and precipitate out of solution, clogging lines and altering composition.

Question 137: The CMS Conditions for Coverage require that a hemodialysis patient's care plan be reviewed and updated at minimum:

Every 6 months
Annually
Only at initiation of dialysis
Monthly, or more frequently when clinically indicated (Correct answer)

Correct answer: Monthly, or more frequently when clinically indicated

CMS requires monthly interdisciplinary team review of each patient's care plan to ensure treatment prescriptions and goals remain appropriate as clinical status changes.

Question 138: According to AAMI TIR No. 12, what is the recommended maximum resistance for the protective earth (ground) conductor in patient-connected medical equipment?

0.5 ohm
0.01 ohm
1.0 ohm
0.1 ohm (Correct answer)

Correct answer: 0.1 ohm

AAMI TIR No. 12 and IEC 60601-1 specify that protective earth resistance must not exceed 0.1 ohm to ensure a reliable low-impedance fault return path that will trip protective overcurrent devices.

Question 139: The ultrafiltration coefficient of a dialyzer refers to the:

pressure difference across the membrane.
pressure in the blood compartment needed to force fluid through the membrane.
fluid that passes through the membrane in 1 minute.
fluid that passes through the membrane in 1 hour. (Correct answer)

Correct answer: fluid that passes through the membrane in 1 hour.

The ultrafiltration coefficient (Kuf) of a dialyzer measures its permeability to water. It indicates how much fluid (in milliliters) will be removed from the blood across the dialyzer membrane per hour for every mmHg of transmembrane pressure. This value is crucial for calculating and controlling the amount of fluid removed from a patient during dialysis.

Question 140: What is the AAMI standard maximum allowable bacterial count in hemodialysis dialysate?

100 CFU/mL (Correct answer)
1000 CFU/mL
500 CFU/mL
10 CFU/mL

Correct answer: 100 CFU/mL

AAMI standards specify that dialysate must contain fewer than 100 CFU/mL of bacteria to be considered safe for hemodialysis treatment.

Question 141: Regional citrate anticoagulation is sometimes used in CRRT. What is the mechanism by which citrate prevents clotting?

Citrate inhibits thrombin directly, similar to argatroban
Citrate chelates ionized calcium in the extracorporeal circuit, and calcium is essential for the coagulation cascade (Correct answer)
Citrate activates antithrombin III to degrade clotting factors
Citrate increases platelet cyclic AMP, preventing platelet aggregation

Correct answer: Citrate chelates ionized calcium in the extracorporeal circuit, and calcium is essential for the coagulation cascade

Citrate binds (chelates) ionized calcium, which is required at multiple steps in the coagulation cascade. By reducing ionized calcium in the circuit to <0.35 mmol/L, clotting is prevented. Calcium is then replaced systemically via a separate infusion.

Question 142: Which document must be completed and maintained for every chemical used in a dialysis facility per OSHA Hazard Communication standards?

Exposure Control Plan
Safety Data Sheet (SDS) (Correct answer)
Material Requisition Form
Equipment Service Log

Correct answer: Safety Data Sheet (SDS)

OSHA's Hazard Communication Standard requires Safety Data Sheets (formerly MSDS) for all hazardous chemicals, providing information on handling, storage, and emergency response.

Question 143: Why are dialysis patients at significantly higher risk for bloodstream infections compared to the general population?

Dialysis patients are required to restrict hand washing to prevent skin dryness
Frequent vascular access cannulation, immunosuppression from uremia, and repeated exposure to healthcare environments (Correct answer)
Dialysis removes all protective antibodies from the blood each session
The dialyzer membrane allows bacteria from dialysate to freely enter the bloodstream

Correct answer: Frequent vascular access cannulation, immunosuppression from uremia, and repeated exposure to healthcare environments

Dialysis patients have impaired immune function due to uremia, repeated needle punctures creating infection entry points, and multiple weekly healthcare contacts increasing exposure. These factors combine to make CRBSI and access infections major causes of morbidity and mortality.

Question 144: In biomedical engineering terms, what does 'applied part' mean in the context of IEC 60601-1 for dialysis equipment?

The part of equipment that comes into physiological contact with the patient (Correct answer)
Software-controlled treatment parameters
Any mechanical component attached to the machine frame
The electrical power supply module

Correct answer: The part of equipment that comes into physiological contact with the patient

Per IEC 60601-1, an 'applied part' is any part of medical electrical equipment that in normal use necessarily comes into physical contact with the patient for the equipment to perform its function.

Question 145: Which two diseases account for the majority of ESRD cases in the United States?

Lupus nephritis and IgA nephropathy
Obstructive uropathy and pyelonephritis
Diabetes mellitus and hypertension (Correct answer)
Glomerulonephritis and polycystic kidney disease

Correct answer: Diabetes mellitus and hypertension

Diabetic nephropathy and hypertensive nephrosclerosis together cause over 60% of new ESRD cases in the US.

Question 146: The potassium concentration in hemodialysis dialysate is typically set at:

0 mEq/L for all patients
Equal to normal plasma potassium (3.5–5.0 mEq/L) for all patients
8–10 mEq/L to prevent hypokalemia
1–4 mEq/L, individualized to the patient's pre-dialysis serum potassium (Correct answer)

Correct answer: 1–4 mEq/L, individualized to the patient's pre-dialysis serum potassium

Dialysate potassium is individualized based on pre-treatment serum levels to safely remove excess potassium without causing dangerous hypokalemia.

Question 147: When inspecting the dialyzer at the end of a hemodialysis session, what finding suggests inadequate anticoagulation?

Elevated venous pressure that normalized during the session
Dark streaks or clots visible in the fiber bundle of the dialyzer (Correct answer)
Clear, straw-colored ultrafiltrate in the drainage line
Pink tinge to the dialysate effluent indicating blood leak

Correct answer: Dark streaks or clots visible in the fiber bundle of the dialyzer

Visible clots (dark streaks or solid areas) in the dialyzer fiber bundle indicate thrombosis within the dialyzer. This reduces effective surface area and dialysis adequacy, suggesting anticoagulation was insufficient or the blood flow rate was too low.

Question 148: Which protection classification under IEC 60601-1 designates equipment with a floating (isolated) patient connection suitable for cardiac applications?

Type BF
Type B
Type CF (Correct answer)
Type AP

Correct answer: Type CF

Type CF ('C' = cardiac, 'F' = floating/isolated) applied parts have the most stringent leakage current limits (10 µA) and isolated patient connections, making them suitable for direct cardiac contact.

Question 149: What is the 'reject water' from a reverse osmosis system?

Product water that failed conductivity testing and is discarded
The pre-filtered water returned to the softener for reprocessing
Dialysate that has passed through the dialyzer and is discarded
The concentrated waste stream containing all filtered contaminants that is drained away (Correct answer)

Correct answer: The concentrated waste stream containing all filtered contaminants that is drained away

RO systems produce two streams: product water (permeate, ~75% of input) and reject water (concentrate, ~25%). The reject stream carries all the removed contaminants and is sent to drain. The recovery rate affects operating cost.

Question 150: What is the purpose of performing a pressure hold test on a dialysis machine?

To verify the integrity of the internal fluid pathways and check for leaks (Correct answer)
To verify conductivity sensor accuracy
To calibrate the ultrafiltration controller
To test the blood pump occlusion

Correct answer: To verify the integrity of the internal fluid pathways and check for leaks

A pressure hold test pressurizes the hydraulic circuit and monitors for pressure decay, confirming there are no leaks in the machine's fluid pathways.

Question 151: What does HIPAA require dialysis facility staff to do regarding patient health information?

Store all records in paper format only
Disclose patient information to any healthcare provider on request
Protect the privacy and confidentiality of all patient health information and disclose it only as permitted by law or patient authorization (Correct answer)
Share patient information freely among all clinical staff regardless of need-to-know

Correct answer: Protect the privacy and confidentiality of all patient health information and disclose it only as permitted by law or patient authorization

HIPAA's Privacy Rule requires dialysis facilities to safeguard protected health information (PHI) and limit disclosures to the minimum necessary for treatment, payment, or operations.

Question 152: Which electrolyte imbalance is of greatest immediate concern in ESRD patients?

Hyponatremia
Hyperkalemia (Correct answer)
Hyperphosphatemia
Hypocalcemia

Correct answer: Hyperkalemia

Hyperkalemia is the most immediately life-threatening electrolyte imbalance in ESRD because elevated potassium can trigger fatal cardiac arrhythmias.

Certified Hemodialysis Bio-Medical Technician (CHBT)

The CHBT is a BONENT certification that validates technical proficiency in hemodialysis bio-medical equipment maintenance, water treatment systems, and clinical support functions within dialysis settings.

150

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180 min

Time Limit

70%

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