BONENT CHT Certified Hemodialysis Technologist Exam — Questions and Answers

Question 1: A patient's AV fistula has a bruit that has changed from soft and continuous to harsh and high-pitched. This change suggests:

Development of a stenosis in the access (Correct answer)
Normal variation with blood pressure changes
Fistula thrombosis
Increased blood flow from successful maturation

Correct answer: Development of a stenosis in the access

A change to a harsh, high-pitched bruit indicates turbulent flow through a narrowed area, suggesting stenosis requiring evaluation.

Question 2: What is the purpose of the dialysate bypass system on a hemodialysis machine?

Recirculate used dialysate
Increase blood flow rate
Route dialysate past the dialyzer when an alarm condition is detected (Correct answer)
Mix concentrate with water

Correct answer: Route dialysate past the dialyzer when an alarm condition is detected

The bypass system diverts dialysate away from the dialyzer when temperature, conductivity, or other alarms occur, protecting the patient from harmful dialysate.

Question 3: Which bloodborne pathogen is most commonly transmitted in hemodialysis units due to shared equipment and environmental contamination?

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

Correct answer: Hepatitis B virus (HBV)

Hepatitis B virus is the most efficiently transmitted bloodborne pathogen in dialysis units due to its high environmental stability and ability to survive on surfaces for days.

Question 4: The acceptable alcohol concentration in hand sanitizers effective for healthcare use against most viruses and bacteria is:

60-95% ethanol or isopropanol (Correct answer)
50% ethanol maximum
10% isopropanol
20-30% ethanol

Correct answer: 60-95% ethanol or isopropanol

Hand sanitizers must contain 60-95% alcohol to denature microbial proteins effectively; lower concentrations lack sufficient antimicrobial activity.

Question 5: What is the preferred vascular access type for chronic hemodialysis patients?

Tunneled central venous catheter
Non-tunneled catheter
Arteriovenous fistula (Correct answer)
Arteriovenous graft

Correct answer: Arteriovenous fistula

The arteriovenous fistula (AVF) is the gold standard vascular access for hemodialysis due to its superior longevity and lower complication rates.

Question 6: Which factor decreases dialysis adequacy (Kt/V) if all other parameters remain constant?

Increasing dialysate flow rate
Using a higher KoA dialyzer
Increased access recirculation (Correct answer)
Increasing blood flow rate

Correct answer: Increased access recirculation

Access recirculation reduces the effective clearance of urea by mixing dialyzed blood back into the arterial draw, lowering effective Kt/V.

Question 7: Before cannulating a patient's arteriovenous fistula, which assessment must ALWAYS be performed first?

Irrigate the fistula site with heparinized saline solution
Measure blood pressure in the arm that contains the fistula
Inspect and palpate the access site for thrill, bruit, redness, swelling, and pain (Correct answer)
Draw blood cultures from the fistula to screen for active infection

Correct answer: Inspect and palpate the access site for thrill, bruit, redness, swelling, and pain

Pre-cannulation assessment requires inspecting for signs of infection (redness, swelling, drainage) and confirming patency by palpating for thrill and auscultating for bruit before inserting any needles.

Question 8: What is the 'rule of 6s' used to assess AV fistula maturity?

6 weeks old, 6 cm long, 6 mm deep
Blood flow >600, length >6 cm, puncture for 6 sessions
Flow >600 mL/min, depth <6 mm, diameter >6 mm
Diameter >6 mm, depth <6 mm, flow >600 mL/min (Correct answer)

Correct answer: Diameter >6 mm, depth <6 mm, flow >600 mL/min

The 'rule of 6s' states a fistula is ready when it has diameter >6 mm, depth <6 mm from skin, and blood flow >600 mL/min.

Question 9: Which type of vascular access is considered the gold standard for chronic hemodialysis?

Arteriovenous graft (AVG)
Arteriovenous fistula (AVF) (Correct answer)
Tunneled central venous catheter
Non-tunneled catheter

Correct answer: Arteriovenous fistula (AVF)

The arteriovenous fistula is preferred because it has the lowest complication rates, longest patency, and best outcomes for long-term hemodialysis.

Question 10: Which chemical is most commonly used as a germicide in manual dialyzer reprocessing?

Isopropyl alcohol 70%
Sodium hypochlorite at 5%
Formaldehyde (4%) (Correct answer)
Hydrogen peroxide 35%

Correct answer: Formaldehyde (4%)

Formaldehyde at 4% has been widely used as a dialyzer reprocessing germicide due to its broad-spectrum antimicrobial efficacy.

Question 11: Which medication is used to reverse heparin anticoagulation in cases of bleeding during hemodialysis?

Vitamin K
Fresh frozen plasma
Tranexamic acid
Protamine sulfate (Correct answer)

Correct answer: Protamine sulfate

Protamine sulfate binds and neutralizes heparin, rapidly reversing its anticoagulant effect.

Question 12: Vascular access care bundles in hemodialysis facilities are designed primarily to reduce:

Dialyzer reuse frequency
Dialysis machine downtime
Catheter-related bloodstream infections (CRBSI) through standardized aseptic technique (Correct answer)
Patient wait times

Correct answer: Catheter-related bloodstream infections (CRBSI) through standardized aseptic technique

Vascular access care bundles standardize evidence-based aseptic practices for catheter connection and disconnection, significantly reducing CRBSI rates.

Question 13: A hemodialysis patient develops a fever (temperature >38°C) during treatment. What is the most likely cause?

Hypoglycemia triggering an adrenergic sympathetic stress response
Excessive ultrafiltration rate causing hemodynamic instability
Bacteremia or a pyrogenic reaction from contaminated water or inadequately reprocessed dialyzer (Correct answer)
Dialysate temperature set below the recommended range causing vasoconstriction

Correct answer: Bacteremia or a pyrogenic reaction from contaminated water or inadequately reprocessed dialyzer

Fever during dialysis most commonly indicates bacteremia from access site infection or a pyrogenic reaction caused by endotoxins from contaminated dialysis water or improperly reprocessed dialyzers.

Question 14: Which action should be performed before reprocessing a dialyzer for reuse?

Test the fiber bundle volume (Correct answer)
Perform a recirculation study
Check TMP at full blood flow
Prime with heparinized saline

Correct answer: Test the fiber bundle volume

Fiber bundle volume (FBV) testing before and after reprocessing determines if the dialyzer retains adequate clearance capacity.

Question 15: Reverse osmosis (RO) in water treatment works primarily by:

Forcing water through a semi-permeable membrane under pressure (Correct answer)
Exchanging sodium ions for calcium and magnesium ions
Exposing water to ultraviolet light
Using activated carbon to adsorb chlorine

Correct answer: Forcing water through a semi-permeable membrane under pressure

RO forces water under high pressure through a membrane that blocks dissolved salts, bacteria, and most contaminants.

Question 16: A patient's pre-dialysis BUN is 80 mg/dL and post-dialysis BUN is 20 mg/dL. What is the URR?

80%
25%
60%
75% (Correct answer)

Correct answer: 75%

URR = (pre-BUN − post-BUN) / pre-BUN × 100 = (80 − 20) / 80 × 100 = 75%.

Question 17: A dialyzer's ultrafiltration coefficient relates 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. Fluid that passes through the membrane in 1 hour. (Correct answer)

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

The ultrafiltration rate of the fluid transfer can be controlled by the dialysis machine by adjusting the hydraulic pressures in the blood and dialysate compartments. The manufacturer assigns an ultrafiltration coefficient (Kuf) to each dialyzer. This is the amount of fluid (measured in milliliters) that can move through the membrane in one hour at a specific pressure difference. As a result, 250 mL (5 x 50) of fluid can be transferred in 1 hour of dialysis using a dialyzer with a Kuf of 5 and a transmembrane pressure of 50 mm Hg. Dialysis removal is an effective method of managing fluid volume and weight because renal failure patients are frequently edematous and have too much water in the interstitial compartment. Diuretic medications are used because the patient's kidneys are not working. Diuretic medications are not very helpful because the patient's kidneys are not functioning.

Question 18: What does a high transmembrane pressure (TMP) alarm during dialysis typically indicate?

Inadequate dialysate temperature
Clotting in the dialyzer (Correct answer)
Air in the blood circuit
Low blood flow rate

Correct answer: Clotting in the dialyzer

Elevated TMP often indicates clotting within the dialyzer fibers, increasing resistance to ultrafiltration.

Question 19: Which vital sign measurement is MOST important to obtain before initiating each hemodialysis treatment?

Pre-treatment weight, blood pressure, pulse, respirations, and temperature (Correct answer)
Temperature only
Pulse oximetry only
Blood pressure only

Correct answer: Pre-treatment weight, blood pressure, pulse, respirations, and temperature

A complete set of pre-treatment vitals (weight, BP, pulse, respirations, temperature) establishes the baseline needed to calculate ultrafiltration goals and detect changes during treatment.

Question 20: What does KUF (ultrafiltration coefficient) measure in a dialyzer?

Blood flow capacity of the dialyzer
Clearance of urea per hour
Dialyzer surface area in square meters
Volume of fluid removed per hour per mmHg of TMP (Correct answer)

Correct answer: Volume of fluid removed per hour per mmHg of TMP

KUF expresses how many milliliters of fluid the dialyzer removes per hour for each mmHg of transmembrane pressure applied.

Question 21: A thrill that is weak or absent at the AV fistula site most likely indicates:

Infiltration of the access
Stenosis or thrombosis of the fistula (Correct answer)
Successful maturation
High fistula blood flow

Correct answer: Stenosis or thrombosis of the fistula

Absence or weakening of the thrill (palpable vibration) suggests stenosis or clot formation reducing blood flow through the fistula.

Question 22: IV iron administration during hemodialysis is timed to coincide with:

The last hour of treatment only
After the blood pump is stopped
The first 30 minutes of treatment (Correct answer)
Any time during dialysis is equally appropriate

Correct answer: The first 30 minutes of treatment

IV iron is typically given in the first 30 minutes of dialysis to allow maximum monitoring time for infusion reactions.

Question 23: The purpose of a UV light unit in a dialysis water treatment system is to:

Reduce bacterial load (Correct answer)
Remove endotoxins
Soften water
Remove heavy metals

Correct answer: Reduce bacterial load

UV irradiation disrupts bacterial DNA, reducing the bioburden in the water distribution system before it reaches patients.

Question 24: Kayexalate (sodium polystyrene sulfonate) is used in dialysis patients to manage which condition?

Hypercalcemia
Hyperkalemia (Correct answer)
Metabolic acidosis
Hyperphosphatemia

Correct answer: Hyperkalemia

Kayexalate is a cation-exchange resin that binds potassium in the GI tract and removes it from the body, used for acute or chronic hyperkalemia.

Question 25: Why is aluminum hydroxide generally avoided as a long-term phosphate binder in dialysis patients?

It is too expensive
It is rapidly dialyzed off
It causes aluminum toxicity leading to dementia and bone disease (Correct answer)
It causes hyperphosphatemia

Correct answer: It causes aluminum toxicity leading to dementia and bone disease

Chronic aluminum hydroxide use leads to aluminum accumulation causing dialysis dementia and adynamic bone disease.

Question 26: Which complication of AVF cannulation is characterized by blood tracking into surrounding tissue during needle insertion?

Stenosis
Infiltration/hematoma (Correct answer)
Aneurysm
Thrombosis

Correct answer: Infiltration/hematoma

Infiltration occurs when the needle is not properly seated in the vessel lumen, allowing blood to extravasate into surrounding tissue and form a hematoma.

Question 27: Which water treatment component is primarily responsible for removing chlorine and chloramines from dialysis water?

Reverse osmosis membrane
Water softener
Activated carbon tank (Correct answer)
Deionizer

Correct answer: Activated carbon tank

Activated carbon tanks adsorb chlorine and chloramines from the water supply before it reaches the reverse osmosis unit.

Question 28: Which medication is commonly used to treat hypotension during hemodialysis?

Metoprolol
Midodrine (Correct answer)
Furosemide
Captopril

Correct answer: Midodrine

Midodrine, an alpha-1 agonist taken orally before dialysis, raises blood pressure by causing vasoconstriction, reducing intradialytic hypotension.

Question 29: Which type of dialyzer membrane is most commonly used in modern hemodialysis and associated with improved biocompatibility?

Unmodified cellulose
Low-flux cellulose acetate
High-flux synthetic (polysulfone, polyethersulfone) (Correct answer)
Cuprophane (cellulose)

Correct answer: High-flux synthetic (polysulfone, polyethersulfone)

High-flux synthetic membranes like polysulfone offer superior biocompatibility, higher middle-molecule clearance, and lower complement activation compared to cellulosic membranes.

Question 30: A blood leak alarm activates during dialysis. What is the first action the technician should take?

Increase blood flow to confirm the alarm
Clamp blood lines and do NOT return blood to patient (Correct answer)
Return blood to patient and disconnect
Check dialysate conductivity

Correct answer: Clamp blood lines and do NOT return blood to patient

When a blood leak is confirmed, blood lines must be clamped and blood should NOT be returned because the dialysate may be contaminated.

Question 31: Two-patient identification checks before initiating hemodialysis include verifying:

Room number and machine number only
Dialyzer brand and needle gauge only
Patient name and date of birth (or second identifier) against the treatment order (Correct answer)
Patient height and weight only

Correct answer: Patient name and date of birth (or second identifier) against the treatment order

Two-patient identifiers (name plus DOB or MRN) verified against the treatment order prevent wrong-patient dialysis, a serious preventable safety event.

Question 32: When cannulating an AVF, the arterial needle should be inserted pointing in which direction relative to blood flow?

Retrograde or antegrade depending on facility protocol and access characteristics (Correct answer)
Perpendicular to the vessel
Always antegrade (toward the heart)
Always retrograde (away from the heart)

Correct answer: Retrograde or antegrade depending on facility protocol and access characteristics

Arterial needle direction (antegrade or retrograde) depends on facility protocol and individual access characteristics to optimize blood flow.

Question 33: The 'buttonhole' or constant-site cannulation technique involves:

Only using the arterial needle
Using a new site every treatment
Rotating between three sites
Inserting needles at the same site and angle each treatment (Correct answer)

Correct answer: Inserting needles at the same site and angle each treatment

The buttonhole technique involves cannulating the exact same site at the same angle each treatment, creating a fibrous tract that reduces pain and aneurysm formation.

Question 34: What is the minimum blood flow rate that a mature arteriovenous fistula should be able to support for adequate hemodialysis?

100 mL/min
350 mL/min (Correct answer)
200 mL/min
600 mL/min

Correct answer: 350 mL/min

A mature AVF should sustain at least 350 mL/min blood flow to support effective hemodialysis treatment.

Question 35: When assessing a newly placed AV graft, how long should the technician typically wait before the first cannulation?

6 months
2-3 weeks (Correct answer)
48-72 hours
24 hours

Correct answer: 2-3 weeks

AV grafts typically require 2-3 weeks of healing before first cannulation to allow incorporation and reduce risk of hematoma or infection.

Question 36: When recirculation in a dialysis access is suspected, which test can confirm it?

Glucose step test or urea-based recirculation test (Correct answer)
Observing needle site appearance
Blood pressure measurement
Checking venous pressure only

Correct answer: Glucose step test or urea-based recirculation test

The glucose step test or urea-based recirculation measurement quantifies the percentage of dialyzed blood re-entering the arterial needle rather than returning to the patient.

Question 37: Which parameter reflects the ability of a dialyzer to clear small molecules like urea through diffusion?

KUF (ultrafiltration coefficient)
Fiber bundle volume
Membrane thickness
KoA (mass transfer area coefficient) (Correct answer)

Correct answer: KoA (mass transfer area coefficient)

KoA (mass transfer area coefficient) is the product of membrane permeability and surface area, determining diffusive clearance of small solutes.

Question 38: What causes foaming in the venous drip chamber during hemodialysis?

Air in the arterial line causing turbulence (Correct answer)
Hemolysis of red blood cells
Low heparin dose
High blood flow rate

Correct answer: Air in the arterial line causing turbulence

Air entering the arterial bloodline creates turbulence in the venous drip chamber, resulting in foam formation.

Question 39: Ultrafiltration in hemodialysis refers to the removal of:

Phosphorus by adsorption
Excess fluid by convection (Correct answer)
Potassium by active transport
Urea and creatinine by diffusion

Correct answer: Excess fluid by convection

Ultrafiltration removes excess fluid from the blood via convective transport driven by transmembrane pressure.

Question 40: Which chemical is NOT required to be tested in dialysis product water by AAMI/ISO standards?

Lead
Aluminum
Caffeine (Correct answer)
Fluoride

Correct answer: Caffeine

AAMI/ISO standards specify testing for a defined list of chemical contaminants including metals and anions, but caffeine is not among them.

Question 41: What is the most common cause of clotting in the extracorporeal circuit during hemodialysis?

High blood flow rate
Low dialysate temperature
Excessive ultrafiltration
Insufficient anticoagulation (Correct answer)

Correct answer: Insufficient anticoagulation

Inadequate heparin or anticoagulation is the most common reason blood clots form in the tubing, dialyzer, or drip chambers.

Question 42: A patient reports new-onset chest pain during hemodialysis. What is the technician's FIRST action?

Reduce the blood flow rate by half and continue monitoring
Apply oxygen via nasal cannula per standing protocol orders
Stop the blood pump and initiate a normal saline bolus immediately
Notify the nurse immediately while remaining with the patient and monitoring vital signs (Correct answer)

Correct answer: Notify the nurse immediately while remaining with the patient and monitoring vital signs

Chest pain during dialysis is a potentially life-threatening symptom; the technician must immediately alert the nurse while staying at bedside to monitor the patient's condition.

Question 43: For a patient with a large body size (high V), which adjustment would best maintain adequate Kt/V?

Reduce blood flow rate
Use a smaller surface area dialyzer
Decrease dialysate flow rate
Increase treatment time or use a higher efficiency dialyzer (Correct answer)

Correct answer: Increase treatment time or use a higher efficiency dialyzer

Larger patients have a higher urea volume of distribution (V), requiring longer treatment times or higher-efficiency dialyzers to achieve adequate Kt/V.

Question 44: The minimum frequency for cleaning and disinfecting dialysis station surfaces (chair, machine, supplies) between patients is:

Once per week
After each patient use, before the next patient is seated (Correct answer)
After every third patient
Once per day at shift end

Correct answer: After each patient use, before the next patient is seated

Dialysis station surfaces must be cleaned and disinfected after each patient to prevent cross-contamination of bloodborne pathogens to the next patient.

Question 45: Which hand hygiene product is NOT effective against Clostridioides difficile (C. diff) spores?

Chlorhexidine scrub
Povidone-iodine scrub
Alcohol-based hand sanitizer (Correct answer)
Soap and water

Correct answer: Alcohol-based hand sanitizer

Alcohol-based hand sanitizers do not kill C. difficile spores; soap and water with mechanical friction is required to physically remove spores from hands.

Question 46: Proper labeling of a reprocessed dialyzer must include:

Dialyzer model number only
Only the patient's name
Patient name, patient ID, number of uses, and date of reprocessing (Correct answer)
Date of reprocessing only

Correct answer: Patient name, patient ID, number of uses, and date of reprocessing

Reprocessed dialyzers must be labeled with the patient's name, ID, use count, and reprocessing date to ensure proper patient-specific tracking and safety.

Question 47: When using a tunneled hemodialysis catheter, the recommended locking solution placed in the catheter lumens between treatments is:

Heparin (1000-5000 units/mL) or citrate locking solution (Correct answer)
Sterile water
Normal saline only
Antibiotic-only solution

Correct answer: Heparin (1000-5000 units/mL) or citrate locking solution

Catheter lumens are locked with heparin or citrate solution between treatments to prevent fibrin occlusion and maintain catheter patency.

Question 48: The 'rope ladder' technique of AVF cannulation involves:

Only cannulating near the anastomosis
Rotating needle sites along the entire length of the fistula (Correct answer)
Using the same holes each treatment
Using two needles on the same segment

Correct answer: Rotating needle sites along the entire length of the fistula

The rope ladder technique distributes needle insertions evenly along the entire fistula length, preventing aneurysm formation at any single site.

Question 49: The maximum recommended ultrafiltration rate to minimize intradialytic hypotension and cardiovascular stress is:

20 mL/kg/hour
13 mL/kg/hour (Correct answer)
5 mL/kg/hour
10 mL/kg/hour

Correct answer: 13 mL/kg/hour

CMS and clinical guidelines recommend keeping ultrafiltration rates below 13 mL/kg/hour to reduce cardiovascular complications and intradialytic hypotension.

Question 50: When priming a dialyzer with saline, the correct direction of flow through the blood compartment is:

Either direction is acceptable
Venous port to arterial port (top to bottom)
Arterial port to venous port (bottom to top) (Correct answer)
Simultaneous flushing from both ports

Correct answer: Arterial port to venous port (bottom to top)

Priming flows from the arterial (inlet) port upward to the venous (outlet) port to expel air from the blood compartment in the direction blood will travel.

Question 51: What does the term 'Kt/V' measure in hemodialysis adequacy?

Dose of dialysis delivered, representing urea clearance relative to urea volume of distribution (Correct answer)
Time on dialysis divided by volume of dialysate used
Ultrafiltration rate relative to body weight
Blood flow rate times treatment time

Correct answer: Dose of dialysis delivered, representing urea clearance relative to urea volume of distribution

Kt/V is a dimensionless index of dialysis adequacy where K = dialyzer clearance, t = treatment time, and V = volume of distribution of urea.

Question 52: Which electrolyte imbalance is most immediately life-threatening during dialysis if not corrected?

Hyperkalemia (Correct answer)
Hyperphosphatemia
Hyponatremia
Hypocalcemia

Correct answer: Hyperkalemia

Severe hyperkalemia can cause fatal cardiac arrhythmias and is a primary indication for emergent dialysis.

Question 53: What is the most probable reason for post-renal failure?

severe dehydration
nephrotoxic drug
glomerulonephritis
benign prostatic hypertrophy (Correct answer)

Correct answer: benign prostatic hypertrophy

The anatomic site of the injury is frequently used to categorize acute renal failure (ARF). Pre-renal failure is frequently brought on by hypotension, which happens when there has been trauma, dehydration, or blood loss and the renal blood flow has been significantly reduced.

Question 54: During priming of the extracorporeal circuit, approximately how much saline is typically used?

1500–2000 mL
700–1000 mL
100–200 mL
300–500 mL (Correct answer)

Correct answer: 300–500 mL

A standard circuit prime uses approximately 300–500 mL of saline to displace air and prepare the blood lines and dialyzer.

Question 55: A patient's pre-dialysis BUN is 80 mg/dL and post-dialysis BUN is 20 mg/dL. What is the URR?

60%
70%
80%
75% (Correct answer)

Correct answer: 75%

URR = (pre-BUN − post-BUN) / pre-BUN × 100 = (80 − 20) / 80 × 100 = 75%.

Question 56: Which blood sample timing is critical for accurate Kt/V calculation?

Post-dialysis sample drawn 30 minutes after treatment ends
Pre-dialysis sample drawn 5 minutes after starting the blood pump
Post-dialysis sample drawn immediately after stopping the blood pump with a slow-flow technique (Correct answer)
Both samples drawn mid-session

Correct answer: Post-dialysis sample drawn immediately after stopping the blood pump with a slow-flow technique

The post-dialysis BUN sample must be drawn at low blood flow (approximately 50–100 mL/min) immediately after stopping to avoid cardiopulmonary recirculation affecting results.

Question 57: A patient suddenly develops chest pain, shortness of breath, and hypotension 15 minutes into treatment. The FIRST action should be to:

Decrease ultrafiltration rate only
Increase blood flow rate to improve clearance
Administer IV saline bolus and continue treatment
Return blood to the patient and stop treatment (Correct answer)

Correct answer: Return blood to the patient and stop treatment

Suspected acute reactions require immediate termination of dialysis and return of blood to the patient to stabilize the patient.

Question 58: Which component of a water treatment system is responsible for removing bacteria and endotoxins through size exclusion?

Sediment filter
Activated carbon
Water softener
Reverse osmosis membrane (Correct answer)

Correct answer: Reverse osmosis membrane

The reverse osmosis membrane removes bacteria, endotoxins, and most dissolved solids through semipermeable filtration.

Question 59: Cinacalcet (Sensipar) is used in dialysis patients to treat which condition?

Metabolic acidosis
Secondary hyperparathyroidism (Correct answer)
Anemia
Hypertension

Correct answer: Secondary hyperparathyroidism

Cinacalcet is a calcimimetic that sensitizes the calcium-sensing receptor on parathyroid cells, suppressing PTH secretion in secondary hyperparathyroidism.

Question 60: When reprocessing a dialyzer with peracetic acid, what is the minimum required dwell time to achieve adequate disinfection?

11 hours (Correct answer)
6 hours
30 minutes
5 minutes

Correct answer: 11 hours

Peracetic acid dialyzer reprocessing requires a minimum 11-hour contact time to ensure effective high-level disinfection per AAMI standards.

Question 61: Which sign indicates that a patient may be experiencing steal syndrome from an AV access?

Swelling of the access arm
Thrill disappearance at anastomosis
Fever and chills during dialysis
Pain, pallor, and coldness of the hand distal to the access (Correct answer)

Correct answer: Pain, pallor, and coldness of the hand distal to the access

Steal syndrome causes ischemia distal to the AV access, presenting as hand pain, pallor, paresthesia, and coldness due to blood being 'stolen' from the distal circulation.

Question 62: What does the term 'Kt/V' measure in hemodialysis adequacy?

Urea clearance normalized to body water volume (Correct answer)
Blood flow rate relative to dialysate flow
Ultrafiltration rate per treatment hour
Transmembrane pressure across the dialyzer

Correct answer: Urea clearance normalized to body water volume

Kt/V quantifies urea clearance (K × time) divided by the patient's urea distribution volume (V); a value ≥1.2 per treatment is the KDOQI minimum.

Question 63: First-use syndrome (type A anaphylactic reaction) during hemodialysis is most classically associated with which dialyzer membrane type?

Ethylene oxide-sterilized AN69 membranes in patients on ACE inhibitors (Correct answer)
Cellulose triacetate membranes
All synthetic membranes equally
High-flux polysulfone

Correct answer: Ethylene oxide-sterilized AN69 membranes in patients on ACE inhibitors

AN69 membranes can adsorb blood contact factor XII activating bradykinin, and ACE inhibitors prevent bradykinin breakdown, causing severe anaphylactic reactions.

Question 64: What does a consistently falling pre-dialysis BUN suggest about a patient's dialysis prescription or status?

The dialyzer is malfunctioning
The blood pump speed is too high
The patient may have decreased protein intake or increased residual renal function (Correct answer)
The patient is receiving too much dialysis

Correct answer: The patient may have decreased protein intake or increased residual renal function

Falling pre-dialysis BUN may indicate reduced dietary protein intake (malnutrition) or improved residual renal function, both warranting clinical evaluation.

Question 65: Which action is required before each dialysis treatment to verify proper blood pathway integrity?

Measuring the dialysate conductivity
Calibrating the blood flow sensor
Conducting a pressure hold test on the blood circuit (Correct answer)
Performing a heparin bolus test

Correct answer: Conducting a pressure hold test on the blood circuit

A pressure hold test confirms there are no leaks in the extracorporeal blood circuit before connecting the patient.

Question 66: A patient's dry weight is best described as:

The patient's weight immediately after dialysis
The weight at which the patient has no signs of fluid overload or dehydration (Correct answer)
The weight determined solely by the patient's BMI
The patient's normal body weight without the dialysis machine connected

Correct answer: The weight at which the patient has no signs of fluid overload or dehydration

Dry weight is the target post-dialysis weight at which the patient is euvolemic — no edema and no signs of intravascular volume depletion.

Question 67: What is the recommended dialysate temperature range for standard hemodialysis?

34–35°C
36–38°C (Correct answer)
39–41°C
42–44°C

Correct answer: 36–38°C

Standard dialysate temperature is maintained at 36–38°C to prevent hypothermia or protein denaturation in the extracorporeal circuit.

Question 68: Standard precautions in hemodialysis require which personal protective equipment (PPE) when handling blood-contaminated items?

N95 mask for all procedures
Gloves only
Gloves and gown for all blood exposures; mask and eye protection when splashing is likely (Correct answer)
No PPE needed for routine care

Correct answer: Gloves and gown for all blood exposures; mask and eye protection when splashing is likely

Standard precautions require gloves for all blood contact, with gown, mask, and eye protection added when blood splash or spraying is anticipated.

Question 69: A technician notices the dialysate conductivity reading is consistently 12.5 mS/cm instead of the target of 14.0 mS/cm. The most likely cause is:

Acid concentrate ratio is too low
Bicarbonate concentrate is depleted or supply line is kinked (Correct answer)
Reverse osmosis water pressure is elevated
Dialysate temperature is too high

Correct answer: Bicarbonate concentrate is depleted or supply line is kinked

Low conductivity typically results from insufficient concentrate delivery; a depleted or blocked bicarbonate supply line reduces the total ionic content of the dialysate.

Question 70: Itching (pruritus) in hemodialysis patients most commonly results from:

Excess fluid removal
Accumulation of uremic toxins, secondary hyperparathyroidism, and inadequate dialysis (Correct answer)
Allergy to dialysate chemicals
Hypotension during treatment

Correct answer: Accumulation of uremic toxins, secondary hyperparathyroidism, and inadequate dialysis

Uremic pruritus results from accumulation of uremic toxins, elevated PTH from secondary hyperparathyroidism, and inadequate removal of middle molecules during dialysis.

Question 71: The 'rope-ladder' technique for AVF cannulation requires:

Rotating needle insertion sites systematically along the full length of the vessel segment (Correct answer)
Inserting needles at a 45-degree angle always
Alternating between the arterial and venous needle sites each session
Using only one consistent site for each needle

Correct answer: Rotating needle insertion sites systematically along the full length of the vessel segment

Rope-ladder technique distributes punctures along the entire usable vessel length, preventing focal aneurysm formation and ensuring even wear.

Question 72: Which complication is most commonly associated with tunneled central venous catheters used for hemodialysis?

Aneurysm formation
Steal syndrome
Catheter-related bloodstream infection (Correct answer)
Pseudoaneurysm

Correct answer: Catheter-related bloodstream infection

Catheter-related bloodstream infection (CRBSI) is the most frequent and serious complication of tunneled dialysis catheters.

Question 73: A patient's arterial pressure monitor reads increasingly negative values during treatment. What is the most likely cause?

Inadequate blood flow from the access (Correct answer)
Clotted dialyzer
Access recirculation
Venous needle kinking

Correct answer: Inadequate blood flow from the access

Increasingly negative arterial pressure indicates the blood pump is working harder to draw blood, usually due to poor flow from the vascular access.

Question 74: Before a reprocessed dialyzer is used on a patient, residual germicide must be tested. Which test confirms formaldehyde removal?

Conductivity test
Colorimetric test using chromotropic acid or equivalent (Correct answer)
Glucose oxidase strip
pH test strip

Correct answer: Colorimetric test using chromotropic acid or equivalent

A colorimetric test (such as chromotropic acid) is used to confirm that formaldehyde levels have been reduced to safe levels before reuse.

Question 75: What does the term 'high-flux dialysis' refer to?

Use of a dialyzer with a high KUF and ability to clear middle molecules (Correct answer)
Use of online hemodiafiltration only
Dialysis performed more than 3 times per week
Use of very high blood flow rates above 500 mL/min

Correct answer: Use of a dialyzer with a high KUF and ability to clear middle molecules

High-flux dialysis uses membranes with a high KUF and large pore size to remove middle molecules in addition to small solutes.

Question 76: The primary purpose of the bicarbonate concentrate in dialysate preparation is to:

Prevent bacterial growth in the system
Replace sodium lost during dialysis
Maintain dialyzer membrane integrity
Correct metabolic acidosis in the patient (Correct answer)

Correct answer: Correct metabolic acidosis in the patient

Bicarbonate in dialysate diffuses into the patient's blood to buffer the metabolic acidosis that accumulates in renal failure.

Question 77: The hepatitis B vaccination series is recommended for which hemodialysis patients?

All susceptible (anti-HBs negative) hemodialysis patients (Correct answer)
Only staff, not patients
Only patients with a history of IV drug use
Only patients under age 40

Correct answer: All susceptible (anti-HBs negative) hemodialysis patients

All hemodialysis patients who are anti-HBs negative (susceptible to HBV) should receive hepatitis B vaccination regardless of age to prevent facility-acquired hepatitis B.

Question 78: Which bacteria is most commonly associated with dialysis water contamination causing pyrogenic reactions?

Staphylococcus aureus
Pseudomonas aeruginosa (Correct answer)
Streptococcus pyogenes
Escherichia coli

Correct answer: Pseudomonas aeruginosa

Pseudomonas aeruginosa thrives in water environments and is a leading cause of gram-negative bacteremia and pyrogenic reactions in dialysis patients.

Question 79: Which factor most directly affects the efficiency of solute clearance in hemodialysis?

Ultrafiltration volume
Patient's body weight
Blood flow rate and dialysate flow rate (Correct answer)
Dialysate temperature

Correct answer: Blood flow rate and dialysate flow rate

Solute clearance is primarily determined by blood flow rate and dialysate flow rate, which drive diffusive transport across the membrane.

Question 80: How many kidneys are still functioning one year after transplantation?

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

Correct answer: 90%

A common kind of treatment for chronic renal illness is kidney transplantation. In the US, about 15,000 are carried out annually. The kidney transplant recipient may get a living related donor (such as a spouse or friend) or a cadaver kidney, which is typically from a non-related person who just passed away. The patient is often matched from the national donor list in the latter scenario. In all situations, blood and tissue type (human leukocyte antigen) matching is crucial for the survival of the organ in the recipient, and living donors should be in good physical and mental health. Up to 20 years or longer may pass after a kidney transplant, almost invariably with the use of immunosuppressive medications that reduce the risk of rejection of disapproval. At one year after surgery, between 89% and 95% of transplanted kidneys are functioning.

Question 81: What minimum water-to-concentrate ratio is used by most proportioning hemodialysis machines?

36:1
40:1
34:1 (Correct answer)
30:1

Correct answer: 34:1

Most proportioning systems dilute bicarbonate or acetate concentrate at a 34:1 (water to concentrate) ratio to create dialysate.

Question 82: A minimum URR of what percentage is recommended for adequate hemodialysis?

75%
45%
65% (Correct answer)
55%

Correct answer: 65%

A URR of at least 65% is the recommended minimum for adequate dialysis, correlating with a Kt/V of approximately 1.2.

Question 83: The Kt/V adequacy target for hemodialysis patients according to KDOQI guidelines is a minimum of:

0.8 per session
1.8 per session
2.5 per session
1.2 per session (Correct answer)

Correct answer: 1.2 per session

KDOQI guidelines recommend a minimum delivered Kt/V of 1.2 per hemodialysis session to ensure adequate small-molecule solute removal.

Question 84: Which practice is PROHIBITED in dialysis treatment areas to prevent cross-contamination between patients?

Wearing gloves for needle removal
Using dedicated carts for medication administration
Bringing medication carts, trays, or supplies used for one patient to another patient's station without disinfection (Correct answer)
Using individual patient supply packs

Correct answer: Bringing medication carts, trays, or supplies used for one patient to another patient's station without disinfection

Medication carts and supplies moved between patient stations without disinfection risk transferring bloodborne pathogens via contaminated surfaces.

Question 85: Hard water syndrome in dialysis is caused by:

Low bicarbonate concentration
Bacterial contamination of the water supply
Excess sodium in the dialysate
Inadequate water treatment allowing calcium and magnesium into dialysate (Correct answer)

Correct answer: Inadequate water treatment allowing calcium and magnesium into dialysate

Hard water syndrome occurs when water softening fails, allowing excess calcium and magnesium to enter dialysate and causing nausea, hypotension, and burning sensations.

Question 86: When testing dialysis water conductivity, a sudden drop in conductivity of the RO product water suggests:

Carbon bed exhaustion
Possible membrane breakthrough (Correct answer)
Softener regeneration needed
Excellent membrane performance

Correct answer: Possible membrane breakthrough

A sudden drop in conductivity of RO product water can paradoxically indicate membrane breakthrough as low-conductivity contaminants pass through.

Question 87: What is the minimum single-pool Kt/V (spKt/V) recommended by KDOQI for thrice-weekly hemodialysis?

1.2 (Correct answer)
1.0
1.4
1.6

Correct answer: 1.2

KDOQI guidelines recommend a minimum spKt/V of 1.2 per session for patients on thrice-weekly hemodialysis.

Question 88: Nocturnal hemodialysis (6–8 hours, 3–6 nights per week) compared to standard hemodialysis offers which primary benefit?

Higher blood flow rates
Eliminates need for dietary restrictions
Requires less anticoagulation
Better clearance of middle molecules and improved phosphate control (Correct answer)

Correct answer: Better clearance of middle molecules and improved phosphate control

Longer nocturnal sessions significantly improve middle molecule clearance and phosphate removal, reducing need for phosphate binders.

Question 89: Which anticoagulant is most frequently used during hemodialysis to prevent clotting in the extracorporeal circuit?

Bivalirudin
Warfarin
Unfractionated heparin (Correct answer)
Low-molecular-weight heparin

Correct answer: Unfractionated heparin

Unfractionated heparin is the standard anticoagulant used during hemodialysis due to its rapid onset, short half-life, and reversibility with protamine.

Question 90: Infiltration of an AV graft during cannulation requires which immediate action?

Inject heparin at the site
Remove the needle, apply pressure, and assess the site (Correct answer)
Increase the UFR to compensate for fluid infiltration
Continue dialysis at a lower blood flow rate

Correct answer: Remove the needle, apply pressure, and assess the site

Upon infiltration, the needle must be removed immediately and firm pressure applied to limit hematoma formation.

Question 91: CDC guidelines recommend that hepatitis B surface antigen (HBsAg)-positive patients in dialysis units should:

Not receive hemodialysis
Be dialyzed in a separate room or area with dedicated equipment (Correct answer)
Be treated in the same area as all other patients
Only be dialyzed using peritoneal dialysis

Correct answer: Be dialyzed in a separate room or area with dedicated equipment

HBsAg-positive patients must be isolated in a separate room or bay with dedicated machines, supplies, and staff to prevent HBV transmission to susceptible patients.

Question 92: What is a patient's 'dry weight' in the context of hemodialysis?

The lowest weight a patient can tolerate without experiencing hypotension or cramps (Correct answer)
Weight used to calculate Kt/V
Weight measured after the patient is completely dehydrated
Weight of the patient without any clothing

Correct answer: The lowest weight a patient can tolerate without experiencing hypotension or cramps

Dry weight (target weight) is the post-dialysis weight at which the patient is euvolemic and does not exhibit signs of over- or under-hydration.

Question 93: After reprocessing, dialyzers must be stored at what temperature to maintain germicide efficacy?

Above 45°C
Below 4°C (refrigerated)
Room temperature 20-25°C (Correct answer)
Body temperature 37°C

Correct answer: Room temperature 20-25°C

Reprocessed dialyzers stored at room temperature (20-25°C) maintain appropriate germicide activity and are accessible for verification testing before use.

Question 94: What is the target hemoglobin range recommended by KDIGO guidelines for dialysis patients receiving ESA therapy?

10–11.5 g/dL (Correct answer)
8–9 g/dL
13–15 g/dL
12–13 g/dL

Correct answer: 10–11.5 g/dL

KDIGO guidelines recommend maintaining hemoglobin between 10–11.5 g/dL for dialysis patients to reduce transfusion risk without increasing cardiovascular events.

Question 95: What is the function of the heparin pump on a dialysis machine?

Regulate ultrafiltration rate
Flush the dialyzer with saline
Deliver anticoagulant at a controlled rate into the arterial blood line (Correct answer)
Monitor patient's clotting time

Correct answer: Deliver anticoagulant at a controlled rate into the arterial blood line

The heparin pump infuses anticoagulant at a preset rate into the arterial blood line to prevent clotting in the extracorporeal circuit.

Question 96: Patients on long-term dialysis are often prescribed active vitamin D analogs such as paricalcitol primarily to:

Lower serum phosphorus levels
Suppress elevated PTH and prevent renal osteodystrophy (Correct answer)
Treat anemia by stimulating erythropoiesis
Improve dialysis adequacy

Correct answer: Suppress elevated PTH and prevent renal osteodystrophy

Active vitamin D analogs suppress parathyroid hormone secretion and promote bone health, preventing renal osteodystrophy in dialysis patients.

Question 97: Which type of dialyzer membrane is made from synthetic polymer and is generally more biocompatible than cellulosic membranes?

Regenerated cellulose
Cuprophan
Polysulfone (Correct answer)
Cellulose acetate

Correct answer: Polysulfone

Polysulfone is a high-flux synthetic membrane with superior biocompatibility compared to cellulosic membranes.

Question 98: The purpose of performing a machine safety check before each hemodialysis treatment includes verifying:

Conductivity, temperature, pH (bicarbonate balance), blood leak detector function, and air detector function (Correct answer)
Only the ultrafiltration goal
Only the blood flow rate setting
Machine serial number and purchase date

Correct answer: Conductivity, temperature, pH (bicarbonate balance), blood leak detector function, and air detector function

Pre-treatment machine safety checks verify that dialysate parameters and safety alarms are properly set and functional before connecting the patient to the extracorporeal circuit.

Question 99: Which patient population should NOT receive reprocessed dialyzers according to infection control principles?

Patients with known or suspected prion disease (CJD) (Correct answer)
HIV-positive patients only
Elderly patients over 65
Diabetic patients

Correct answer: Patients with known or suspected prion disease (CJD)

Patients with Creutzfeldt-Jakob disease (CJD) or other prion diseases must not receive reprocessed dialyzers because prions cannot be inactivated by standard germicides.

Question 100: Which class of medications is most commonly used to treat anemia in dialysis patients?

Vitamin B12 injections
Granulocyte colony-stimulating factors
Iron supplements only
Erythropoiesis-stimulating agents (ESAs) (Correct answer)

Correct answer: Erythropoiesis-stimulating agents (ESAs)

Erythropoiesis-stimulating agents (ESAs) such as epoetin alfa and darbepoetin stimulate red blood cell production in anemic dialysis patients.

Question 101: When manually cleaning a dialyzer during reprocessing, water used for rinsing must meet which standard?

Distilled water only
AAMI dialysis-grade water quality (Correct answer)
Sterile injectable water
Standard tap water quality

Correct answer: AAMI dialysis-grade water quality

All water used in dialyzer reprocessing must meet AAMI dialysis-quality water standards to prevent contamination of the dialyzer with chemical or microbial impurities.

Question 102: What does 'interdialytic weight gain' primarily reflect in a hemodialysis patient?

Weight gained from increased skeletal muscle mass between treatments
Improvement in the patient's nutritional status between sessions
Change in the patient's bone density over the course of dialysis therapy
Fluid accumulated between dialysis sessions due to inability to excrete water (Correct answer)

Correct answer: Fluid accumulated between dialysis sessions due to inability to excrete water

Interdialytic weight gain predominantly reflects fluid accumulation between sessions, since ESRD patients cannot excrete excess water through normal renal function.

Question 103: A patient on hemodialysis develops sudden rigors, fever of 103°F, and hypotension 30 minutes into treatment. The most likely cause is:

Pyrogenic reaction from endotoxin contamination (Correct answer)
Air embolism
Hypovolemia from ultrafiltration
Dialyzer reaction Type A

Correct answer: Pyrogenic reaction from endotoxin contamination

Pyrogenic reactions present with fever and rigors and are caused by endotoxin fragments entering the blood from contaminated dialysate.

Question 104: The recommended approach to CVC exit site care in hemodialysis includes:

Cleaning with chlorhexidine or povidone-iodine and applying a sterile dry dressing at each dialysis visit (Correct answer)
Only cleaning the exit site monthly
Cleaning only with normal saline, no dressing required
Using antibiotic ointment on all exit sites routinely

Correct answer: Cleaning with chlorhexidine or povidone-iodine and applying a sterile dry dressing at each dialysis visit

Regular antiseptic cleaning and sterile dry dressing application at each dialysis session reduces exit site contamination and catheter-related infection rates.

Question 105: A dialysis patient taking calcium carbonate as a phosphate binder should be instructed to take it:

With meals to bind dietary phosphate (Correct answer)
At bedtime
After dialysis sessions only
On an empty stomach 1 hour before meals

Correct answer: With meals to bind dietary phosphate

Calcium carbonate must be taken with meals to bind phosphate from food in the GI tract before it can be absorbed.

Question 106: What is the generally recommended maximum ultrafiltration rate to reduce the risk of intradialytic hypotension?

Less than 5 mL/kg/hour
Greater than 20 mL/kg/hour
Less than 13 mL/kg/hour (Correct answer)
Exactly 10 mL/kg/hour regardless of patient size

Correct answer: Less than 13 mL/kg/hour

Current evidence-based guidelines recommend keeping ultrafiltration rates below 13 mL/kg/hour to minimize cardiovascular stress and intradialytic hypotension risk.

Question 107: The primary reason high-flux dialyzers require ultrapure dialysate is:

They cost more to manufacture
They use more electricity
Their large pore size allows back-filtration of dialysate into the blood compartment (Correct answer)
High-flux dialyzers do not require ultrapure dialysate

Correct answer: Their large pore size allows back-filtration of dialysate into the blood compartment

High-flux membranes can allow dialysate to back-filter into the blood compartment due to transmembrane pressure gradients, making dialysate purity critical to prevent endotoxin transfer.

Question 108: A dialysis technician notices that the RO reject rate has dropped significantly. This most likely indicates:

RO membrane fouling or failure (Correct answer)
Improved source water quality
Softener malfunction only
The RO membrane is working more efficiently

Correct answer: RO membrane fouling or failure

A drop in RO reject rate (less water being rejected) often signals membrane fouling or failure, reducing its ability to reject contaminants.

Question 109: Which finding on physical examination of a central venous catheter (CVC) exit site requires immediate intervention?

Purulent drainage, redness, and warmth at exit site (Correct answer)
Slight scabbing at the exit site
Clear serous fluid at exit site day 1 post-insertion
Dry, intact healing around the cuff

Correct answer: Purulent drainage, redness, and warmth at exit site

Purulent drainage with redness and warmth at a CVC exit site indicates infection requiring immediate evaluation, culture, and likely catheter removal.

Question 110: Residual kidney function (RKF) in a dialysis patient contributes to overall solute clearance. How is it typically measured?

By glomerular filtration rate formula (eGFR)
By 24-hour urine collection for urea and creatinine clearance (Correct answer)
By a 2-hour post-dialysis blood draw
By serum creatinine level alone

Correct answer: By 24-hour urine collection for urea and creatinine clearance

Residual kidney function is quantified by collecting a 24-hour urine sample to measure urinary urea and creatinine clearance between dialysis sessions.

Question 111: URR (urea reduction ratio) is calculated as:

(Post-BUN − Pre-BUN) ÷ Post-BUN × 100
(Pre-BUN − Post-BUN) ÷ Pre-BUN × 100 (Correct answer)
Post-BUN ÷ Pre-BUN × 100
Pre-BUN ÷ Post-BUN × 100

Correct answer: (Pre-BUN − Post-BUN) ÷ Pre-BUN × 100

URR = (Pre-BUN − Post-BUN) ÷ Pre-BUN × 100, expressing the percentage reduction in blood urea nitrogen during a dialysis session.

Question 112: Why should antihypertensive medications ideally be withheld on the morning of hemodialysis?

They may cause excessive hypotension during fluid removal (Correct answer)
They increase clotting risk during treatment
They interfere with dialysis membrane function
They are dialyzed out and lose effectiveness

Correct answer: They may cause excessive hypotension during fluid removal

Taking antihypertensives before dialysis combined with fluid removal can lead to severe intradialytic hypotension.

Question 113: Which organism is the most common cause of catheter-related bloodstream infections in hemodialysis patients?

Candida species
Escherichia coli
Staphylococcus aureus (Correct answer)
Pseudomonas aeruginosa

Correct answer: Staphylococcus aureus

Staphylococcus aureus, including MRSA, is the most common cause of CRBSI in hemodialysis patients and is associated with high morbidity and mortality.

Question 114: Reuse of dialyzers in the United States is regulated by which federal agency?

CMS (Centers for Medicare & Medicaid Services) via Conditions for Coverage (Correct answer)
EPA only
FDA only
OSHA only

Correct answer: CMS (Centers for Medicare & Medicaid Services) via Conditions for Coverage

CMS regulates dialyzer reuse through the ESRD Conditions for Coverage, requiring facilities to follow AAMI standards for safe reprocessing practices.

Question 115: Peracetic acid/hydrogen peroxide (Renalin/Minncare) used in dialyzer reprocessing is advantageous because:

It breaks down into non-toxic products (acetic acid, water, oxygen) (Correct answer)
It requires no germicide residual testing
It requires no rinsing before reuse
It is safe to inhale in concentrated form

Correct answer: It breaks down into non-toxic products (acetic acid, water, oxygen)

Peracetic acid decomposes into acetic acid, water, and oxygen, making it environmentally safer and decomposing to harmless residuals after adequate contact time.

Question 116: What minimum needle gauge is required to achieve blood flow rates of 400-500 mL/min during hemodialysis?

16-17 gauge (Correct answer)
21 gauge
14 gauge only
25 gauge

Correct answer: 16-17 gauge

16-17 gauge needles are standard for hemodialysis to allow blood flow rates of 300-500 mL/min without excessive hemolysis or pressure.

Question 117: Which conductivity value would most likely trigger the dialysate bypass alarm?

10.0 mS/cm (Correct answer)
13.5 mS/cm
14.0 mS/cm
15.0 mS/cm

Correct answer: 10.0 mS/cm

A conductivity of 10.0 mS/cm is significantly below the normal range of 13–17 mS/cm and would trigger bypass, indicating improper mixing.

Question 118: Which phosphate binder is calcium-based and most commonly used in dialysis patients?

Lanthanum carbonate
Calcium carbonate (Correct answer)
Aluminum hydroxide
Sevelamer

Correct answer: Calcium carbonate

Calcium carbonate is a widely used, calcium-based phosphate binder that binds dietary phosphate in the GI tract.

Question 119: What is the acceptable conductivity range for dialysate used in standard hemodialysis?

2–4 mS/cm
13–17 mS/cm (Correct answer)
8–16 mS/cm
20–25 mS/cm

Correct answer: 13–17 mS/cm

Standard hemodialysate conductivity ranges from approximately 13 to 17 mS/cm, reflecting the ionic concentration of properly diluted concentrate.

Question 120: A blood leak test on a reprocessed dialyzer involves:

Testing patient blood for dialysate contamination
Measuring urea clearance only
Checking for visible blood in the dialysate during treatment
Applying pressure to the blood compartment and checking for leaks into the dialysate side (Correct answer)

Correct answer: Applying pressure to the blood compartment and checking for leaks into the dialysate side

The blood leak test pressurizes the blood compartment of the dialyzer and checks whether any fluid crosses into the dialysate compartment, indicating membrane rupture.

Question 121: A patient becomes unresponsive with a pulse during dialysis. After calling for help, the next priority is:

Continue dialysis at reduced blood flow
Stop ultrafiltration, reduce blood flow, position flat, assess airway and initiate emergency response (Correct answer)
Administer heparin IV
Increase dialysate temperature to 38°C

Correct answer: Stop ultrafiltration, reduce blood flow, position flat, assess airway and initiate emergency response

An unresponsive patient requires immediate airway assessment, stopping ultrafiltration, positioning supine, and activating the emergency response system.

Question 122: The minimum acceptable chloramine level in treated dialysis water per AAMI standards is:

Less than 0.1 mg/L (Correct answer)
Less than 1.0 mg/L
Less than 0.5 mg/L
Less than 2.0 mg/L

Correct answer: Less than 0.1 mg/L

AAMI standards require chloramine levels below 0.1 mg/L in treated water to prevent hemolytic anemia in dialysis patients.

Question 123: A dialyzer's molecular weight cutoff is 12,000 daltons. Which of the following compounds would not be able to cross the dialysate membrane?

phosphate
albumin (Correct answer)
urea
sodium

Correct answer: albumin

Each dialyzer membrane has a molecular weight cutoff (in daltons) that determines the size of the molecules that can pass through it. These may range from 3000 to 15,000 daltons. Small molecules (e.g., sodium, potassium, phosphate, urea, water) pass through the filter easily while large molecules, such as proteins (e.g., albumin with a molecular weight of 15,000 daltons), such as urea, are difficult to pass

Question 124: A tunneled dialysis catheter is locked with which solution between dialysis sessions to maintain patency?

Tissue plasminogen activator (tPA)
Antibiotic solution
Heparin or citrate locking solution (Correct answer)
Normal saline only

Correct answer: Heparin or citrate locking solution

Heparin or citrate locking solutions fill the catheter lumens between sessions to prevent thrombus formation and maintain patency.

Question 125: Which electrolyte imbalance is most commonly treated with sodium bicarbonate supplementation in dialysis patients?

Hyperphosphatemia
Metabolic acidosis (Correct answer)
Hypercalcemia
Hyperkalemia

Correct answer: Metabolic acidosis

Dialysis patients frequently develop metabolic acidosis due to inability to excrete acid, treated with bicarbonate in dialysate or oral supplementation.

Question 126: A venous pressure alarm that is consistently low may indicate which problem?

Clotted venous drip chamber
Needle dislodgement from the access (Correct answer)
High blood flow rate
Kinked venous blood line

Correct answer: Needle dislodgement from the access

A consistently low venous pressure can indicate that the venous needle has dislodged from the access, reducing resistance in the return line.

Question 127: A dialysis patient has a pre-BUN of 80 mg/dL and a post-BUN of 20 mg/dL. What is the URR?

75% (Correct answer)
40%
80%
25%

Correct answer: 75%

(80 − 20) ÷ 80 × 100 = 60 ÷ 80 × 100 = 75%, indicating adequate dialysis.

Question 128: Which occupational exposure risk is greatest for staff performing manual dialyzer reprocessing without proper PPE?

Electrical hazard from automated equipment
Radiation exposure
Chemical exposure to germicides (formaldehyde, peracetic acid) (Correct answer)
Ergonomic injury only

Correct answer: Chemical exposure to germicides (formaldehyde, peracetic acid)

Staff performing dialyzer reprocessing face the greatest risk from chemical exposure to germicides like formaldehyde (carcinogen) and peracetic acid (corrosive), requiring proper PPE.

Question 129: When setting up a hemodialysis machine, what does the technician verify by performing a 'pressure hold test'?

Blood pump accuracy
Integrity of the blood circuit for leaks (Correct answer)
Ultrafiltration controller accuracy
Dialysate flow rate calibration

Correct answer: Integrity of the blood circuit for leaks

A pressure hold test verifies that the blood circuit is intact and free of leaks before connecting the patient.

Question 130: Increasing which treatment parameter is the most effective way to improve Kt/V in a hemodialysis patient?

Ultrafiltration volume
Heparin dose
Treatment time (Correct answer)
Dialysate sodium concentration

Correct answer: Treatment time

Extending treatment time is the most effective single intervention for improving Kt/V because it directly increases the 't' component.

Question 131: When applying post-dialysis compression to an AV fistula site, how long should pressure typically be maintained?

5–10 minutes (Correct answer)
15–20 minutes
1–2 minutes
30–40 minutes

Correct answer: 5–10 minutes

Pressure should be applied for 5–10 minutes after needle removal to achieve hemostasis without occluding the fistula.

Question 132: Which sign during fistula assessment indicates possible stenosis or outflow obstruction?

Bruit heard at anastomosis only
Pulsatile, hard-feeling access with high venous pressures (Correct answer)
Soft, easily compressible thrill
Low arterial pressures during dialysis

Correct answer: Pulsatile, hard-feeling access with high venous pressures

A pulsatile, hard-feeling access with elevated venous pressures during dialysis suggests downstream stenosis impeding blood flow.

Question 133: What is the AAMI maximum allowable bacterial count in dialysate?

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

Correct answer: 200 CFU/mL

AAMI standards allow a maximum of 200 CFU/mL of bacteria in dialysate.

Question 134: What is the purpose of sodium modeling during hemodialysis?

Increase urea clearance
Reduce dialysis time needed
Use variable dialysate sodium to improve hemodynamic stability and reduce cramps (Correct answer)
Prevent hypercalcemia

Correct answer: Use variable dialysate sodium to improve hemodynamic stability and reduce cramps

Sodium modeling uses a higher dialysate sodium at the start and gradually decreases it, helping stabilize blood pressure and reduce muscle cramps.

Question 135: What is the normal oxygen saturation (SpO2) range for a healthy adult as measured by pulse oximetry?

95–100% (Correct answer)
75–85%
90–94%
85–90%

Correct answer: 95–100%

Normal pulse oximetry SpO2 for a healthy adult is 95–100%; values below 95% may indicate hypoxemia and warrant clinical assessment.

Question 136: The AAMI/ISO standard for endotoxin levels in hemodialysis water is less than:

0.1 EU/mL
1.0 EU/mL
0.25 EU/mL (Correct answer)
2.0 EU/mL

Correct answer: 0.25 EU/mL

Standard hemodialysis water must contain less than 0.25 EU/mL of endotoxins per AAMI/ISO standards.

Question 137: A patient reports arm pain distal to the fistula during and after dialysis, with cold fingers. This is most consistent with:

Carpal tunnel syndrome unrelated to access
Normal post-dialysis fatigue
Access-related ischemic mononeuropathy (steal syndrome) (Correct answer)
High blood flow through the access being beneficial

Correct answer: Access-related ischemic mononeuropathy (steal syndrome)

Pain and coldness distal to an AVF or graft suggests vascular steal syndrome where the access diverts blood from the distal limb.

Question 138: What is the primary concern when administering EPO (erythropoietin) to a dialysis patient with uncontrolled hypertension?

EPO is ineffective in hypertensive patients
EPO depletes iron stores faster in hypertension
EPO can further increase blood pressure and risk of stroke (Correct answer)
EPO lowers blood pressure dangerously

Correct answer: EPO can further increase blood pressure and risk of stroke

ESA therapy can raise blood pressure and increase stroke risk, requiring blood pressure control before and during ESA administration.

Question 139: Which organization publishes the Conditions for Coverage (CfC) that dialysis facilities must meet to receive Medicare reimbursement?

The Joint Commission
CMS (Centers for Medicare & Medicaid Services) (Correct answer)
CDC
AAMI

Correct answer: CMS (Centers for Medicare & Medicaid Services)

CMS publishes and enforces the ESRD Conditions for Coverage, which establish the minimum standards dialysis facilities must meet for Medicare certification.

Question 140: Patient safety reporting systems in dialysis facilities are most effective when they use:

Physician-only reporting channels
External regulatory reporting only
Mandatory punitive reporting only
Non-punitive, anonymous reporting to encourage near-miss and error disclosure (Correct answer)

Correct answer: Non-punitive, anonymous reporting to encourage near-miss and error disclosure

Non-punitive reporting cultures encourage staff to report near-misses and errors without fear of punishment, enabling learning and systemic safety improvements.

Question 141: The Kt/V target recommended by KDOQI guidelines for thrice-weekly hemodialysis patients is a minimum of:

0.8
1.2 (Correct answer)
1.8
1.4

Correct answer: 1.2

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

Question 142: Elevated venous pressure during hemodialysis (above 250 mmHg at a 400 mL/min flow rate) most likely indicates:

Elevated blood pressure
Arterial needle malposition
Venous stenosis or outflow obstruction (Correct answer)
Normal finding in all patients

Correct answer: Venous stenosis or outflow obstruction

Persistently high venous pressures suggest stenosis or obstruction downstream from the venous needle impeding blood return to the patient.

Question 143: Which alarm on a hemodialysis machine requires the technician to immediately clamp the blood lines and stop the blood pump?

Air detector alarm (Correct answer)
Low arterial pressure alarm
High venous pressure alarm
Blood leak alarm

Correct answer: Air detector alarm

An air detector alarm signals air in the venous line, requiring immediate clamping and stopping the blood pump to prevent an air embolism.

Question 144: What is the normal range for dialysate sodium concentration used in most adult hemodialysis treatments?

135–145 mEq/L (Correct answer)
150–160 mEq/L
160–170 mEq/L
120–130 mEq/L

Correct answer: 135–145 mEq/L

Dialysate sodium is typically set between 135–145 mEq/L to match normal plasma sodium and prevent osmotic imbalances.

Question 145: Catheter-related bloodstream infection (CRBSI) in hemodialysis patients most commonly presents with:

Fever with or without rigors, often without localizing signs at the catheter site (Correct answer)
Hypertension and weight gain
Elevated potassium levels
Exit site redness only

Correct answer: Fever with or without rigors, often without localizing signs at the catheter site

CRBSI typically presents with fever and chills occurring during or shortly after dialysis, often without obvious local catheter site infection, requiring blood cultures.

Question 146: What is the primary advantage of the buttonhole (constant-site) cannulation technique?

Faster access maturation
Higher blood flow rates
Reduced aneurysm formation and less pain with cannulation (Correct answer)
Better clearance of middle molecules

Correct answer: Reduced aneurysm formation and less pain with cannulation

The buttonhole technique creates a consistent scar tunnel that reduces pain and minimizes aneurysm formation compared to rope ladder cannulation.

Question 147: What is the mechanism of action of sevelamer (Renvela) as a phosphate binder?

Non-calcium, non-metal polymer that binds phosphate in the intestine (Correct answer)
Chelates phosphate in the blood
Increases renal phosphate excretion
Binds phosphate through calcium exchange in the GI tract

Correct answer: Non-calcium, non-metal polymer that binds phosphate in the intestine

Sevelamer is a non-absorbed, non-calcium polymer that binds dietary phosphate in the GI tract without adding a calcium or metal load.

Question 148: Which test is used to detect chloramine in dialysis water?

DPD test
Nitrazine test
Silver nitrate test
OT test (Correct answer)

Correct answer: OT test

The OT (orthotolidine) test is used specifically to detect chloramine, while the DPD test detects free chlorine.

Question 149: The immediate action when air embolism is suspected during hemodialysis is:

Clamp the venous line, stop the blood pump, and position patient in left lateral Trendelenburg (Correct answer)
Flush with normal saline immediately
Increase blood flow rate to push air through
Administer heparin IV

Correct answer: Clamp the venous line, stop the blood pump, and position patient in left lateral Trendelenburg

Clamping the venous line and stopping the pump prevents more air from entering; left lateral Trendelenburg traps air in the right ventricle apex away from the pulmonary vasculature.

Question 150: When dialyzing a patient with active pulmonary tuberculosis, which additional precaution is required beyond standard precautions?

No additional precautions beyond standard
Contact precautions only
Droplet precautions with surgical mask
Airborne precautions with N95 respirator and negative-pressure room if available (Correct answer)

Correct answer: Airborne precautions with N95 respirator and negative-pressure room if available

Active pulmonary tuberculosis requires airborne precautions because M. tuberculosis is transmitted via small airborne particles that remain suspended in air for extended periods.

Question 151: A patient on hemodialysis develops sudden shortness of breath, chest tightness, and hives during treatment. This presentation most suggests:

Dialysis disequilibrium
Normal first-use reaction — continue dialysis
Anaphylactic reaction to dialyzer or blood tubing (Correct answer)
Pulmonary edema from fluid overload

Correct answer: Anaphylactic reaction to dialyzer or blood tubing

Sudden dyspnea, chest tightness, and urticaria are classic signs of anaphylaxis requiring immediate treatment cessation and emergency intervention.

BONENT CHT Certified Hemodialysis Technologist Exam

The BONENT Certified Hemodialysis Technologist/Technician (CHT) Exam evaluates competency in hemodialysis water treatment, dialysis equipment operation, vascular access management, medications, dialysis adequacy, reprocessing, infection control, and emergency management of dialysis complications.

150

Questions

180 min

Time Limit

75%

To Pass

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