BONENT CHT Certified Hemodialysis Technologist Exam — Questions and Answers

Question 1: Hard water syndrome in dialysis is caused by:

Bacterial contamination of the water supply
Low bicarbonate concentration
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 2: A thrill that is weak or absent at the AV fistula site most likely indicates:

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

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 3: 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 4: The following are the main methods used to clear low-molecular-weight compounds via dialysis:

convection
diffusion (Correct answer)
solvent drag
adsorption

Correct answer: diffusion

Clearance (K) is the amount of blood that can be cleared of a specific solute in a given amount of time. Based on blood and dialysis flow rates, membrane properties, the solute's molecular weight, size, and charge, and other factors, the manufacturer determines the clearance for a given solute. Diffusion from the high-concentration to the low-concentration side of the membrane removes the majority of low-molecular weight solutes during dialysis, with the rate also being temperature-dependent. Large molecules typically traverse the membrane via solvent drag (convection). The amount of solute that passes through the membrane while the remainder is rejected or adsorbed is indicated by the sieving coefficient (SC). A SC of 0.4. As a result, a SC of 0.4 indicates that 40% of a specific solute will flow through the membrane. Although cellulose membranes have a tendency to absorb more than synthetic hydrophobic ones, the majority of tiny proteins are eliminated from the circulation via adsorption to the membrane. Adsorbed membranes are more biocompatible, however they may reduce convection and diffusion.

Question 5: Which conductivity value would most likely trigger the dialysate bypass alarm?

10.0 mS/cm (Correct answer)
14.0 mS/cm
13.5 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 6: The hepatitis B vaccination series is recommended for which hemodialysis patients?

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

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 7: Which vascular access assessment finding before cannulation is most concerning and should prompt notification of the nurse before proceeding?

Warm skin temperature of the extremity containing the access
A palpable thrill along the length of the arteriovenous fistula
Absence of bruit on auscultation over the access site (Correct answer)
Visible, well-distended veins with adequate vessel prominence

Correct answer: Absence of bruit on auscultation over the access site

Absence of the expected bruit (and thrill) over an AV fistula suggests possible thrombosis or access failure, which requires nursing evaluation before cannulation.

Question 8: During a hemodialysis treatment, the blood leak detector alarms. The technician should FIRST:

Increase blood flow rate to maintain clearance
Document the alarm and continue monitoring
Clamp the blood lines and return blood to the patient
Check the dialysate for pink or red discoloration to confirm a membrane rupture (Correct answer)

Correct answer: Check the dialysate for pink or red discoloration to confirm a membrane rupture

Confirming blood leak by inspecting dialysate for discoloration is the first step before clamping lines and stopping treatment.

Question 9: IV iron administration during hemodialysis is timed to coincide with:

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

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 10: Which AV graft material is most commonly used for hemodialysis access today?

Bovine carotid artery
Dacron
Silicone
Expanded polytetrafluoroethylene (ePTFE) (Correct answer)

Correct answer: Expanded polytetrafluoroethylene (ePTFE)

Expanded PTFE (Gore-Tex) is the most widely used synthetic graft material due to its durability and biocompatibility.

Question 11: Which factor decreases dialysis adequacy (Kt/V) if all other parameters remain constant?

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

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

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

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 13: A blood leak test on a reprocessed dialyzer involves:

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

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

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

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

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

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 16: Which of the following skeletal structures attaches to the ureter and directly transports urine there?

glomerulus
pelvis (Correct answer)
cortex
calyx

Correct answer: pelvis

The kidney is a bilateral organ about the size of a fist with a hard outer capsule.

Question 17: A reprocessed dialyzer with visible clotted blood remaining in the fiber bundle after cleaning should be:

Discarded immediately (Correct answer)
Soaked longer in germicide only
Used if it passes the blood leak test
Used for one additional treatment only

Correct answer: Discarded immediately

Visible clotted blood indicates inadequate cleaning, potentially harboring microorganisms; such dialyzers must be discarded regardless of other test results.

Question 18: Catheter-related bloodstream infection (CRBSI) in hemodialysis patients most commonly presents with:

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

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 19: What is the recommended minimum length of maturation time for a new AV fistula before first cannulation?

1–2 weeks
4–6 weeks (Correct answer)
2–4 weeks
6–8 weeks

Correct answer: 4–6 weeks

KDOQI guidelines recommend waiting at least 4–6 weeks after fistula creation before cannulation to allow adequate maturation.

Question 20: Which of the following is the correct procedure when an air detector alarm sounds during hemodialysis?

Silence the alarm and continue treatment at reduced pump speed
Clamp the venous line immediately and stop the blood pump (Correct answer)
Increase ultrafiltration rate to compensate
Flush the circuit with saline to push air back to the dialyzer

Correct answer: Clamp the venous line immediately and stop the blood pump

When an air detector alarm triggers, the venous line must be clamped immediately and the blood pump stopped to prevent air embolism from reaching the patient.

Question 21: 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)
Standard tap water quality
Sterile injectable water

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 22: What is the acceptable pre-dialysis systolic blood pressure range that typically allows hemodialysis treatment to proceed without intervention?

90–180 mmHg (Correct answer)
Less than 90 mmHg
Greater than 200 mmHg
Exactly 120 mmHg

Correct answer: 90–180 mmHg

Most dialysis centers allow treatment when pre-dialysis systolic BP is between 90–180 mmHg; values outside this range require nursing assessment before proceeding.

Question 23: What is the minimum single-pool Kt/V (spKt/V) recommended by KDOQI for thrice-weekly hemodialysis?

1.6
1.4
1.2 (Correct answer)
1.0

Correct answer: 1.2

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

Question 24: What is the AAMI maximum allowable bacterial count in dialysate?

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

Correct answer: 200 CFU/mL

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

Question 25: A patient's AV fistula has a palpable thrill that has become very soft with a high-pitched bruit. This change most likely indicates:

Successful maturation of the fistula
Venous stenosis causing increased resistance (Correct answer)
Arterial steal syndrome
Normal variation between treatments

Correct answer: Venous stenosis causing increased resistance

A high-pitched bruit and diminished thrill indicate turbulent, high-velocity flow through a narrowed segment, suggesting venous stenosis.

Question 26: When assessing a newly placed AV graft, how long should the technician typically wait before the first cannulation?

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

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

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

Correct answer: Catheter-related bloodstream infection

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

Question 28: 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)
Binds phosphate through calcium exchange in the GI tract
Increases renal phosphate excretion
Chelates phosphate in the blood

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

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

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 30: 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)
Only be dialyzed using peritoneal dialysis
Be treated in the same area as all other patients

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 31: URR (urea reduction ratio) is calculated as:

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

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

1.8 per session
0.8 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 33: Patients on long-term dialysis are often prescribed active vitamin D analogs such as paricalcitol primarily to:

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

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

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

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

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

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

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

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 37: Which action is the technician's FIRST priority when a patient reports sudden chest pain and difficulty breathing during dialysis?

Increase the dialysate flow rate to improve clearance
Slow the blood pump to 100 mL/min and observe
Administer oxygen and continue treatment at reduced rate
Notify the charge nurse or physician immediately and assess for air embolism (Correct answer)

Correct answer: Notify the charge nurse or physician immediately and assess for air embolism

Sudden chest pain with dyspnea during dialysis is a medical emergency potentially indicating air embolism, cardiac event, or hemolysis requiring immediate physician notification.

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

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

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: How often should product water be tested for bacteria in a dialysis facility?

Monthly (Correct answer)
Quarterly
Weekly
Daily

Correct answer: Monthly

AAMI guidelines require dialysis product water to be tested for bacteria at least monthly.

Question 40: 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 41: The primary purpose of the bicarbonate concentrate in dialysate preparation is to:

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

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

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

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 43: What is 'access recirculation' in hemodialysis?

Blood flowing backward through the fistula
Cleaned blood being re-drawn into the arterial needle before returning to the body (Correct answer)
Dialysate recirculating in the machine
Heparin recirculating through the blood circuit

Correct answer: Cleaned blood being re-drawn into the arterial needle before returning to the body

Access recirculation occurs when dialyzed blood returning from the venous needle is immediately re-drawn into the arterial needle, reducing treatment efficiency.

Question 44: 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 45: What is the recommended dialysate temperature range for standard hemodialysis?

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

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 46: The minimum recommended blood flow rate for adequate hemodialysis in most adult patients is:

100-150 mL/min
500-600 mL/min
200-250 mL/min
300-400 mL/min (Correct answer)

Correct answer: 300-400 mL/min

Blood flow rates of 300-400 mL/min are recommended to achieve adequate solute clearance (Kt/V ≥1.2) in standard hemodialysis.

Question 47: Proper labeling of a reprocessed dialyzer must include:

Patient name, patient ID, number of uses, and date of reprocessing (Correct answer)
Date of reprocessing only
Only the patient's name
Dialyzer model number 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 48: What does a high transmembrane pressure (TMP) alarm during dialysis typically indicate?

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

Correct answer: Clotting in the dialyzer

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

Question 49: 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
Better clearance of middle molecules and improved phosphate control (Correct answer)
Requires less anticoagulation

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

Integrity of the blood circuit for leaks (Correct answer)
Blood pump accuracy
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 51: Which alarm on a hemodialysis machine requires the technician to immediately clamp the blood lines and stop the blood pump?

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

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

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

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

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

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 54: Which antibiotic class should be used with caution in dialysis patients due to risk of accumulation and ototoxicity?

Penicillins
Aminoglycosides (Correct answer)
Cephalosporins
Macrolides

Correct answer: Aminoglycosides

Aminoglycosides (e.g., gentamicin, tobramycin) are renally eliminated and accumulate in dialysis patients, increasing risk of hearing loss and vestibular damage.

Question 55: Which method is used to estimate the weekly standard Kt/V (stdKt/V) for comparing different dialysis schedules?

Daugirdas formula
Gotch formula
Leypoldt/Depner calculation (Correct answer)
URR percentage

Correct answer: Leypoldt/Depner calculation

The Leypoldt/Depner calculation of standard Kt/V allows comparison of different dialysis schedules (e.g., daily vs. thrice-weekly) by expressing weekly urea clearance in comparable terms.

Question 56: Dialysis disequilibrium syndrome most commonly occurs in:

Patients using high-flux membranes
Chronic stable dialysis patients with high Kt/V
Patients receiving hemodiafiltration
New patients or those with very high pre-dialysis BUN who are dialyzed too aggressively (Correct answer)

Correct answer: New patients or those with very high pre-dialysis BUN who are dialyzed too aggressively

Rapid solute removal in uremic patients creates an osmotic gradient causing cerebral edema; it is most common in first dialysis treatments.

Question 57: A dialyzer's molecular weight cutoff is 12,000 daltons. Which of the following compounds would not be able to cross the dialysate membrane?

sodium
urea
phosphate
albumin (Correct answer)

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

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

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

Anemia
Metabolic acidosis
Hypertension
Secondary hyperparathyroidism (Correct answer)

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

36:1
34:1 (Correct answer)
40:1
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 61: A patient develops pink-tinged blood in the dialysate effluent during treatment. This MOST LIKELY indicates:

Blood leak through a ruptured membrane (Correct answer)
Dialyzer clotting
Incorrect dialysate pH
Hemolysis from kinking of blood lines

Correct answer: Blood leak through a ruptured membrane

Pink or red dialysate effluent indicates a blood leak through the dialyzer membrane and requires immediate treatment termination.

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

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

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

Hypovolemia from ultrafiltration
Pyrogenic reaction from endotoxin contamination (Correct answer)
Air embolism
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 64: Which practice is PROHIBITED in dialysis treatment areas to prevent cross-contamination between patients?

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

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

Pseudomonas aeruginosa (Correct answer)
Streptococcus pyogenes
Staphylococcus aureus
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 66: OSHA's Bloodborne Pathogens Standard requires that hemodialysis technicians use which type of precautions with all patients?

Contact precautions only for HBV-positive patients
Airborne precautions for all dialysis patients
Standard (Universal) Precautions with all patients (Correct answer)
Droplet precautions for all vascular access procedures

Correct answer: Standard (Universal) Precautions with all patients

Standard Precautions treat all patient blood and body fluids as potentially infectious, requiring gloves, face protection, and gowns as appropriate.

Question 67: What is the normal range for dialysate sodium concentration used in most adult hemodialysis treatments?

135–145 mEq/L (Correct answer)
120–130 mEq/L
150–160 mEq/L
160–170 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 68: How many kidneys are still functioning one year after transplantation?

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

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 69: An arteriovenous shunt (AVS) and an arteriovenous fistula (AVF) vary primarily by having an?

AVF requires an external tube
AVF is entirely within the arm (Correct answer)
AVF is more likely to become clotted or infected
AVS is entirely within the arm

Correct answer: AVF is entirely within the arm

Repeated vascular access is necessary because hemodialysis must be performed repeatedly, typically three times a week for four hours.

Question 70: What is the target hemoglobin range recommended by KDIGO guidelines for dialysis patients receiving ESA therapy?

8–9 g/dL
12–13 g/dL
10–11.5 g/dL (Correct answer)
13–15 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 71: What is the maximum allowable level of chloramine in dialysis water according to AAMI standards?

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

Correct answer: 0.1 mg/L

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

Question 72: Chronic renal failure is accompanied by ALL OF THE FOLLOWING, EXCEPT:

hypoparathyroidism (Correct answer)
low hemoglobin
hyperphosphatemia
hyperkalemia

Correct answer: hypoparathyroidism

Chronic renal failure is characterized by a wide range of blood, protein, and electrolyte abnormalities. Due to recurrent blood loss, iron deficiency, and decreased erythropoietin secretion by the sick kidney, anemia is a relatively prevalent condition. Inadequate calcitriol impairs calcium absorption, while insufficient tubular excretion of phosphate causes high phosphate levels. The parathyroid gland is stimulated by a low calcium level to create more parathyroid hormone, resulting in secondary hyperparathyroidism. Calcium buildup in the heart and blood vessels could develop from this. These individuals frequently have elevated potassium levels, which could be fatal.

Question 73: Which bloodborne pathogen is most commonly transmitted in hemodialysis units due to shared equipment and environmental contamination?

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

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

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

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 75: Two-patient identification checks before initiating hemodialysis include verifying:

Patient name and date of birth (or second identifier) against the treatment order (Correct answer)
Patient height and weight only
Dialyzer brand and needle gauge only
Room number and machine number 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 76: Patient safety reporting systems in dialysis facilities are most effective when they use:

External regulatory reporting only
Mandatory punitive reporting only
Physician-only reporting channels
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 77: 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 78: Infiltration of an AV graft during cannulation requires which immediate action?

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

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 79: In the US, the following factors are the most typical causes of chronic kidney disease:

glomerulonephritis
hypertension
polycystic kidney disease
diabetes (Correct answer)

Correct answer: diabetes

The most frequent cause of chronic renal failure (CRF) in the US is diabetes mellitus. Future incidence of CRF may increase due to the rise in type 2 diabetes (which affects 90% of diabetic patients) brought on by the obesity epidemic. The most likely cause of diabetic nephropathy is endovascular injury to the renal arteries. The second most common factor causing CRF is hypertension. The so-called essential type, in which the precise reason is uncertain, predominates. In the first few years of this decade, kidney failure due to hypertension affected around 27% of dialysis patients. With its harmful effects, hypertension can also be brought on by renal disease or renal artery stenosis. Among other causes of CRF are glomerular illnesses polycystic illness, too. Cancer, kidney infections, AIDS, systemic lupus erythematosus, and sickle cell disease are less frequent causes of CRF.

Question 80: A patient with a tunneled cuffed catheter has blood flow rates consistently below 250 mL/min despite repositioning. The most appropriate next step is:

Increase blood pump speed to force higher flows
Notify the charge nurse or physician of suspected catheter malfunction (Correct answer)
Increase heparin dose and continue treatment
Reverse the lines (arterial to venous port) as a temporary measure

Correct answer: Notify the charge nurse or physician of suspected catheter malfunction

Persistent low flow rates despite repositioning suggest catheter dysfunction (fibrin sheath or thrombus) that requires physician evaluation and possible intervention.

Question 81: Increasing which treatment parameter is the most effective way to improve Kt/V in a hemodialysis patient?

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

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 82: 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
Increased blood flow from successful maturation
Fistula thrombosis

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 83: The maximum number of times a dialyzer may be reused is determined by:

A fixed 10-use maximum in all facilities
Federal law mandating a fixed maximum of 30 uses
Patient preference only
The dialyzer's TCV, blood leak test, and visual inspection at each reprocessing (Correct answer)

Correct answer: The dialyzer's TCV, blood leak test, and visual inspection at each reprocessing

No federally mandated fixed maximum exists; dialyzers are reused as long as they pass TCV (≥80%), blood leak, and visual inspection criteria at each reprocessing.

Question 84: Residual kidney function (RKF) in a dialysis patient contributes to overall solute clearance. How is it typically measured?

By 24-hour urine collection for urea and creatinine clearance (Correct answer)
By a 2-hour post-dialysis blood draw
By glomerular filtration rate formula (eGFR)
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 85: During hemodialysis, the transmembrane pressure (TMP) suddenly increases above the alarm limit. This MOST LIKELY indicates:

Excessive heparin administration
Clotting in the dialyzer or venous line (Correct answer)
Hypertension in the patient
Low blood flow rate

Correct answer: Clotting in the dialyzer or venous line

A sudden rise in TMP suggests clot formation increasing resistance to flow in the dialyzer or blood lines.

Question 86: What is the purpose of a water softener in a dialysis water treatment system?

Remove calcium and magnesium ions (Correct answer)
Remove chlorine
Remove bacteria
Adjust pH

Correct answer: Remove calcium and magnesium ions

Water softeners use ion exchange to remove calcium and magnesium ions, preventing scale buildup that can damage the RO membrane.

Question 87: Kayexalate (sodium polystyrene sulfonate) is used in dialysis patients to manage which condition?

Hypercalcemia
Metabolic acidosis
Hyperkalemia (Correct answer)
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 88: Peracetic acid/hydrogen peroxide (Renalin/Minncare) used in dialyzer reprocessing is advantageous because:

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

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

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

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

1.4
1.2 (Correct answer)
0.8
1.8

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 91: What is the recommended minimum treatment time for a thrice-weekly hemodialysis session?

2 hours
4 hours
3.5 hours
3 hours (Correct answer)

Correct answer: 3 hours

KDOQI guidelines recommend a minimum of 3 hours per session for thrice-weekly hemodialysis for most patients.

Question 92: What does the term 'high-flux dialysis' refer to?

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

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 93: According to AAMI guidelines, a dialyzer should be rejected for reuse if the total cell volume (TCV) falls below what percentage of the original volume?

50%
70%
90%
80% (Correct answer)

Correct answer: 80%

AAMI standards require dialyzers to be discarded if TCV falls below 80% of original volume, as this indicates significant fiber loss affecting clearance.

Question 94: During routine hemodialysis, how frequently should vital signs be monitored at a minimum to meet standard practice requirements?

Only when the patient complains of a symptom
Every 30 minutes throughout the entire treatment (Correct answer)
Every 2 hours throughout the treatment session
Once at the beginning of treatment only

Correct answer: Every 30 minutes throughout the entire treatment

Standard dialysis practice requires vital signs to be assessed at minimum every 30 minutes throughout treatment to enable early detection of complications.

Question 95: Which chemical is most commonly used to disinfect the dialysis water distribution loop?

Bleach only
Peracetic acid (Correct answer)
Isopropyl alcohol
Glutaraldehyde

Correct answer: Peracetic acid

Peracetic acid is widely used to disinfect dialysis water distribution loops due to its effectiveness against biofilm and gram-negative organisms.

Question 96: Which type of dialyzer membrane is made from synthetic polymer and is generally more biocompatible than cellulosic membranes?

Cellulose acetate
Polysulfone (Correct answer)
Regenerated cellulose
Cuprophan

Correct answer: Polysulfone

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

Question 97: When recirculation in a dialysis access is suspected, which test can confirm it?

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

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

Clearance of urea per hour
Dialyzer surface area in square meters
Blood flow capacity of the dialyzer
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 99: What is the function of the heparin pump on a dialysis machine?

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

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

Needle dislodgement from the access (Correct answer)
Clotted venous drip chamber
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 101: A patient's arterial pressure monitor reads increasingly negative values during treatment. What is the most likely cause?

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

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 102: Which parameter is measured by the ionic dialysance monitor on modern dialysis machines as a real-time surrogate for urea clearance?

Blood flow rate
Dialyzer fiber bundle volume
Transmembrane pressure
Dialysate conductivity changes (Correct answer)

Correct answer: Dialysate conductivity changes

Ionic dialysance monitors measure changes in dialysate conductivity to estimate small-solute clearance as a real-time surrogate for urea Kt/V.

Question 103: Itching (pruritus) in hemodialysis patients most commonly results from:

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

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 104: 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 105: Which chemical is most commonly used as a germicide in manual dialyzer reprocessing?

Formaldehyde (4%) (Correct answer)
Isopropyl alcohol 70%
Sodium hypochlorite at 5%
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 106: The 'rope ladder' technique of AVF cannulation involves:

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

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

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

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.

Question 108: What is the AAMI maximum action level for bacterial counts in dialysis water?

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

Correct answer: 100 CFU/mL

AAMI standards set the action level for bacterial contamination in dialysis water at 100 CFU/mL, requiring corrective action when exceeded.

Question 109: Which complication is specifically associated with the use of a tunneled central venous catheter for dialysis access?

Catheter-related bloodstream infection (CRBSI) (Correct answer)
Arterial aneurysm formation
Steal syndrome
High venous pressure secondary to stenosis

Correct answer: Catheter-related bloodstream infection (CRBSI)

Tunneled catheters have the highest infection rate among access types, with CRBSI being the most serious and life-threatening complication.

Question 110: Vascular access care bundles in hemodialysis facilities are designed primarily to reduce:

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

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

1–2 minutes
15–20 minutes
5–10 minutes (Correct answer)
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 112: Which of the following dialysate abnormalities is most likely to cause acute hemolysis in dialysis patients?

Normal dialysate temperature of 37°C
Dialysate pH of 7.35
Hypo-osmolar dialysate (low sodium or diluted dialysate) (Correct answer)
Dialysate sodium of 140 mEq/L

Correct answer: Hypo-osmolar dialysate (low sodium or diluted dialysate)

Hypo-osmolar dialysate causes osmotic lysis of red blood cells as water moves into the cells, resulting in acute hemolysis which can be fatal.

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

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

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: What is the purpose of a break point chlorination test in dialysis water treatment?

Check RO membrane integrity
Determine the chloramine removal capacity of carbon tanks (Correct answer)
Calibrate conductivity meters
Measure total dissolved solids

Correct answer: Determine the chloramine removal capacity of carbon tanks

Break point chlorination testing verifies that the activated carbon tanks can adequately remove chloramine before it reaches the RO membrane.

Question 115: For a patient with a large body size (high V), which adjustment would best maintain adequate Kt/V?

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

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 116: Which of the following is the MOST appropriate needle gauge for cannulating a well-developed AV fistula?

21-gauge
14-gauge
18-gauge
16-gauge (Correct answer)

Correct answer: 16-gauge

16-gauge needles are standard for AV fistula cannulation, balancing adequate blood flow (≥200 mL/min) with minimizing vessel trauma.

Question 117: 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:

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

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

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

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

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

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 120: What is the primary clinical purpose of establishing a patient's 'dry weight' in hemodialysis?

To set the optimal blood flow rate for the treatment session
To determine the target post-dialysis weight and guide the amount of fluid removal (Correct answer)
To assess the patient's nutritional protein intake between treatments
To calculate the appropriate dose of erythropoiesis-stimulating agents

Correct answer: To determine the target post-dialysis weight and guide the amount of fluid removal

Dry weight (target weight) is the post-dialysis weight at which the patient is considered euvolemic, guiding the ultrafiltration goal for each treatment.

Question 121: What is a patient's 'dry weight' in the context of hemodialysis?

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

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

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

Correct answer: Protamine sulfate

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

Question 123: Which hand hygiene product is NOT effective against Clostridioides difficile (C. diff) spores?

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

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 124: 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 125: During priming of the extracorporeal circuit, approximately how much saline is typically used?

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

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 126: 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
Using only one consistent site for each needle
Alternating between the arterial and venous needle sites each session

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

Captopril
Furosemide
Metoprolol
Midodrine (Correct answer)

Correct answer: Midodrine

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

Question 128: Which electrolyte abnormality is most immediately life-threatening in the dialysis patient with missed treatments?

Hyperkalemia (Correct answer)
Hyperphosphatemia
Hypermagnesemia
Hypernatremia

Correct answer: Hyperkalemia

Hyperkalemia causes fatal cardiac arrhythmias and is the most immediately dangerous electrolyte abnormality in patients who miss dialysis treatments.

Question 129: A dialyzer's ultrafiltration coefficient relates to the:

pressure difference across the membrane.
fluid that passes through the membrane in 1 minute.
pressure in the blood compartment needed to force fluid through the membrane.
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 130: A patient's pre-dialysis blood pressure is 200/110 mmHg. After initiating treatment and removing 1 L of fluid, BP falls to 80/50 mmHg. The technician should first:

Immediately terminate treatment and return all blood
Increase the ultrafiltration rate to remove fluid faster
Stop ultrafiltration and administer a 200–300 mL normal saline bolus (Correct answer)
Administer oral antihypertensive medication

Correct answer: Stop ultrafiltration and administer a 200–300 mL normal saline bolus

Intradialytic hypotension is managed first by stopping UF and administering a saline challenge to restore circulating volume.

Question 131: What is the minimum blood flow rate that a mature arteriovenous fistula should be able to support for adequate hemodialysis?

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

Correct answer: 350 mL/min

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

Question 132: Which active form of vitamin D is most commonly prescribed to dialysis patients?

Ergocalciferol (D2)
Cholecalciferol (D3)
Calcitriol (1,25-dihydroxyvitamin D) (Correct answer)
25-hydroxyvitamin D

Correct answer: Calcitriol (1,25-dihydroxyvitamin D)

Calcitriol is the active form of vitamin D prescribed to dialysis patients because failed kidneys cannot perform the final hydroxylation step.

Question 133: Which anticoagulant is most frequently used during hemodialysis to prevent clotting in the extracorporeal circuit?

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

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

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 135: Where should the arterial needle be placed in relation to the venous needle when cannulating an AV fistula?

Downstream from venous needle (toward heart)
In the opposite arm
Adjacent to the venous needle
At least 2–3 cm upstream from venous needle (toward access) (Correct answer)

Correct answer: At least 2–3 cm upstream from venous needle (toward access)

The arterial needle is placed upstream (toward the anastomosis) and at least 2–3 cm from the venous needle to minimize recirculation.

Question 136: Which vital sign measurement is MOST important to obtain before initiating each hemodialysis treatment?

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

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

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

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

Recirculate used dialysate
Route dialysate past the dialyzer when an alarm condition is detected (Correct answer)
Increase blood flow rate
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 139: A dialysis technician accidentally sustains a needlestick injury from a patient's used hemodialysis needle. The FIRST action should be:

Immediately wash the wound with soap and water, then report the exposure (Correct answer)
Apply alcohol and continue working
Apply a tourniquet above the injury
Wait to see if symptoms develop before reporting

Correct answer: Immediately wash the wound with soap and water, then report the exposure

Immediate washing with soap and water removes contaminants from the wound; prompt reporting is mandatory for exposure evaluation, source patient testing, and post-exposure prophylaxis.

Question 140: A technician notices the venous pressure alarm is consistently high during a treatment. This most likely indicates:

Stenosis or clotting near the venous needle site (Correct answer)
High blood flow rate through a properly functioning fistula
A kinked arterial line
Low heparin levels in the circuit

Correct answer: Stenosis or clotting near the venous needle site

Elevated venous pressure indicates resistance to blood return, commonly caused by stenosis, needle malposition, or clotting at the venous access site.

Question 141: Which type of dialyzer membrane is most commonly used in modern hemodialysis and associated with improved biocompatibility?

Low-flux cellulose acetate
Cuprophane (cellulose)
High-flux synthetic (polysulfone, polyethersulfone) (Correct answer)
Unmodified 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 142: The 'buttonhole' or constant-site cannulation technique involves:

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

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

Hyperkalemia
Hyperphosphatemia
Hypercalcemia
Metabolic acidosis (Correct answer)

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 144: What is the purpose of sodium modeling during hemodialysis?

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

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

Excessive ultrafiltration
High blood flow rate
Low dialysate temperature
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 146: The purpose of a UV light unit in a dialysis water treatment system is to:

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

Correct answer: Reduce bacterial load

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

Question 147: A dialysis technician notices that the RO reject rate has dropped significantly. This most likely indicates:

Improved source water quality
Softener malfunction only
RO membrane fouling or failure (Correct answer)
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 148: The minimum frequency for cleaning and disinfecting dialysis station surfaces (chair, machine, supplies) between patients is:

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

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

Check TMP at full blood flow
Perform a recirculation study
Test the fiber bundle volume (Correct answer)
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 150: Which complication is characterized by swelling of the entire arm on the side of an AV access?

Access thrombosis
Steal syndrome
Central venous stenosis (Correct answer)
Aneurysm

Correct answer: Central venous stenosis

Central venous stenosis obstructs venous return from the entire arm, causing diffuse swelling, particularly common with prior subclavian catheter placement.

Question 151: Which phosphate binder is calcium-based and most commonly used in dialysis patients?

Sevelamer
Aluminum hydroxide
Lanthanum carbonate
Calcium carbonate (Correct answer)

Correct answer: Calcium carbonate

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

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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