BONENT CHT Certified Hemodialysis Technologist Exam — Questions and Answers

Question 1: Which AV graft material is most commonly used for hemodialysis access today?

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

Correct answer: Expanded polytetrafluoroethylene (ePTFE)

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

Question 2: Residual kidney function (RKF) in a dialysis patient contributes to overall solute clearance. How is it typically measured?

By serum creatinine level alone
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)

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 3: A patient on dialysis reports muscle cramps in both legs during the last hour of treatment. The MOST likely contributing factor is:

High dialysate sodium concentration
Hyperkalemia from inadequate dialysis
Hypercalcemia from dialysate calcium
Rapid or excessive fluid removal causing hypovolemia (Correct answer)

Correct answer: Rapid or excessive fluid removal causing hypovolemia

Intradialytic muscle cramps are most commonly caused by rapid or aggressive ultrafiltration leading to volume depletion and reduced muscle perfusion.

Question 4: Which antibiotic class should be used with caution in dialysis patients due to risk of accumulation and ototoxicity?

Cephalosporins
Macrolides
Aminoglycosides (Correct answer)
Penicillins

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

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

Correct answer: Reduce bacterial load

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

Question 6: Cinacalcet (Sensipar) is used in dialysis patients to treat which condition?

Secondary hyperparathyroidism (Correct answer)
Hypertension
Anemia
Metabolic acidosis

Correct answer: Secondary hyperparathyroidism

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

Question 7: The purpose of performing a machine safety check before each hemodialysis treatment includes verifying:

Machine serial number and purchase date
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

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

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

Correct answer: 75%

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

Question 9: Pyrogenic reactions during hemodialysis are characterized by:

Fever, chills, and rigors occurring 30-90 minutes into treatment, with no positive blood culture required (Correct answer)
Sudden hypotension without fever
Seizures and altered mental status only
Rash and bronchospasm

Correct answer: Fever, chills, and rigors occurring 30-90 minutes into treatment, with no positive blood culture required

Pyrogenic reactions caused by endotoxin exposure present with fever, chills, and rigors typically 30-90 minutes into dialysis and do not require bacteremia to occur.

Question 10: Which of the following dialysate abnormalities is most likely to cause acute hemolysis in dialysis patients?

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

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

Return blood to patient and disconnect
Check dialysate conductivity
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 12: What is the most common cause of clotting in the extracorporeal circuit during hemodialysis?

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

Correct answer: Insufficient anticoagulation

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

Question 13: Which action is the technician's FIRST priority when a patient reports sudden chest pain and difficulty breathing during dialysis?

Administer oxygen and continue treatment at reduced rate
Increase the dialysate flow rate to improve clearance
Slow the blood pump to 100 mL/min and observe
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 14: 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 15: CDC guidelines recommend that hepatitis B surface antigen (HBsAg)-positive patients in dialysis units should:

Not receive hemodialysis
Only be dialyzed using peritoneal dialysis
Be dialyzed in a separate room or area with dedicated equipment (Correct answer)
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 16: Which type of vascular access has the highest long-term patency rate for hemodialysis?

Arteriovenous fistula (AVF) (Correct answer)
Temporary tunneled catheter
Arteriovenous graft (AVG)
Non-tunneled catheter

Correct answer: Arteriovenous fistula (AVF)

AVFs have the highest long-term patency and lowest infection risk, making them the preferred vascular access for hemodialysis.

Question 17: Which is the correct technique for removing needles from an AV access after hemodialysis?

Remove the arterial needle first, then the venous needle
Either order is acceptable if pressure is applied
Remove the venous needle first, then the arterial needle (Correct answer)
Remove both needles simultaneously and apply pressure

Correct answer: Remove the venous needle first, then the arterial needle

The venous needle is removed first to prevent blood from being pumped through the arterial needle into a clamped circuit, then the arterial needle is removed.

Question 18: What is the purpose of the dialysate bicarbonate concentration during hemodialysis?

To increase blood pressure
To prevent clotting in the circuit
To reduce phosphorus levels
To correct metabolic acidosis (Correct answer)

Correct answer: To correct metabolic acidosis

Bicarbonate in dialysate diffuses into the blood to buffer acids and correct the metabolic acidosis common in ESRD patients.

Question 19: A venous pressure alarm that is consistently low may indicate which problem?

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

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

Blood flow rate and dialysate flow rate (Correct answer)
Dialysate temperature
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 21: What does the term 'rejection rate' refer to in reverse osmosis?

Percentage of bacteria removed
Percentage of dissolved solids removed by the membrane (Correct answer)
Number of contaminants rejected per hour
Rate at which water is rejected to drain

Correct answer: Percentage of dissolved solids removed by the membrane

RO rejection rate is the percentage of dissolved solids that the membrane removes from the feed water, typically 95–99%.

Question 22: Why should antihypertensive medications ideally be withheld on the morning of hemodialysis?

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

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

Non-tunneled catheter
Arteriovenous graft (AVG)
Arteriovenous fistula (AVF) (Correct answer)
Tunneled central venous 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 24: Nitrate contamination in dialysis water is particularly dangerous because it causes:

Hemolytic anemia
Hypercalcemia
Hyperkalemia
Methemoglobinemia (Correct answer)

Correct answer: Methemoglobinemia

High nitrate levels in dialysis water convert hemoglobin to methemoglobin, which cannot carry oxygen, causing methemoglobinemia.

Question 25: What is 'access recirculation' in hemodialysis?

Cleaned blood being re-drawn into the arterial needle before returning to the body (Correct answer)
Dialysate recirculating in the machine
Blood flowing backward through the fistula
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 26: Which anticoagulant is most frequently used during hemodialysis to prevent clotting in the extracorporeal circuit?

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

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

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

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

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

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

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

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

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

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 31: Which of the following BEST describes the 'buttonhole' cannulation technique for AV fistulas?

Using the same needle insertion site and angle every treatment to create a track (Correct answer)
Using only blunt needles in a randomly selected site
Inserting the needle at a 90-degree angle each time
Rotating needle insertion sites with each treatment

Correct answer: Using the same needle insertion site and angle every treatment to create a track

The buttonhole technique uses the exact same puncture site and angle repeatedly, forming a fibrous tunnel that allows blunt needle insertion and reduces trauma.

Question 32: Which sign during fistula assessment indicates possible stenosis or outflow obstruction?

Pulsatile, hard-feeling access with high venous pressures (Correct answer)
Soft, easily compressible thrill
Bruit heard at anastomosis only
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 33: 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 34: During a hemodialysis treatment, the blood leak detector alarms. The technician should FIRST:

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

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 35: 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 36: Which vital sign change most commonly signals the onset of intradialytic hypotension during hemodialysis?

Sustained heart rate above 100 bpm for 10 minutes
Decrease in respiratory rate below 12 breaths per minute
Drop in systolic blood pressure of ≥20 mmHg accompanied by symptoms (Correct answer)
Sudden increase in body temperature above 38°C

Correct answer: Drop in systolic blood pressure of ≥20 mmHg accompanied by symptoms

Intradialytic hypotension is clinically defined as a drop in systolic BP of ≥20 mmHg associated with symptoms such as dizziness, nausea, or muscle cramps.

Question 37: During hemodialysis, a sudden drop in the venous pressure alarm most likely indicates which problem?

Air bubbles accumulating in the venous blood line
Needle dislodgment or disconnection in the venous return line (Correct answer)
High blood flow rate causing circuit overpressure
Dialyzer fiber clotting increasing circuit resistance

Correct answer: Needle dislodgment or disconnection in the venous return line

A sudden drop in venous pressure typically indicates needle dislodgment or a disconnection in the venous return line, which can cause rapid, life-threatening blood loss.

Question 38: What is the mechanism of action of sevelamer (Renvela) as a phosphate binder?

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

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

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

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

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

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

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

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

EPA only
FDA 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 43: Patient safety reporting systems in dialysis facilities are most effective when they use:

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

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 44: 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 45: IV iron administration during hemodialysis is timed to coincide with:

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

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

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

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

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

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

Regenerated cellulose
Cellulose acetate
Cuprophan
Polysulfone (Correct answer)

Correct answer: Polysulfone

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

Question 49: A patient's pre-dialysis weight is 75 kg and their established dry weight is 73 kg. What is the patient's interdialytic weight gain?

148 kg
2 kg (Correct answer)
0.5 kg
73 kg

Correct answer: 2 kg

Interdialytic weight gain is calculated as pre-dialysis weight minus dry weight: 75 kg − 73 kg = 2 kg, representing fluid accumulated since the last treatment.

Question 50: When recirculation in a dialysis access is suspected, which test can confirm it?

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

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 51: 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 52: The minimum acceptable chloramine level in treated dialysis water per AAMI standards is:

Less than 1.0 mg/L
Less than 0.1 mg/L (Correct answer)
Less than 2.0 mg/L
Less than 0.5 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 53: Elevated venous pressure during hemodialysis (above 250 mmHg at a 400 mL/min flow rate) most likely indicates:

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

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

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

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 55: 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
Pulmonary edema from fluid overload
Anaphylactic reaction to dialyzer or blood tubing (Correct answer)

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 56: Dialysis disequilibrium syndrome is most likely to occur in which patient population?

Patients with low blood urea nitrogen (BUN)
First-time dialysis patients with very high BUN levels (Correct answer)
Elderly patients with normal kidney function
Patients on dialysis for more than 10 years

Correct answer: First-time dialysis patients with very high BUN levels

Dialysis disequilibrium occurs most often in first-time dialysis patients with severely elevated BUN, as rapid urea removal creates osmotic gradients causing cerebral edema.

Question 57: What is the minimum single-pool Kt/V (spKt/V) recommended by KDOQI for thrice-weekly hemodialysis?

1.0
1.6
1.2 (Correct answer)
1.4

Correct answer: 1.2

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

Question 58: Which conductivity value would most likely trigger the dialysate bypass alarm?

14.0 mS/cm
13.5 mS/cm
10.0 mS/cm (Correct answer)
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 59: 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)
Blood leak alarm
Low arterial pressure alarm
High venous pressure 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 60: The 'rope ladder' technique of AVF cannulation involves:

Rotating needle sites along the entire length of the fistula (Correct answer)
Using the same holes each treatment
Only cannulating near the anastomosis
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 61: In dialyzer reprocessing with peracetic acid, the minimum residual volume that must be rinsed out before patient use is determined by:

The manufacturer's priming volume (Correct answer)
Required cell volume ratio retention
Membrane surface area
Dialyzer fiber count

Correct answer: The manufacturer's priming volume

The dialyzer must be rinsed thoroughly based on priming volume to dilute reprocessing chemicals below safe exposure limits before patient reuse.

Question 62: What is the recommended dialysate temperature range for standard hemodialysis?

42–44°C
39–41°C
34–35°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 63: 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 64: What does 'dynamic venous pressure monitoring' during dialysis help detect?

Air embolism
Outflow stenosis in the venous segment of an access (Correct answer)
Patient hypotension
Clotting in the dialyzer

Correct answer: Outflow stenosis in the venous segment of an access

Elevated dynamic venous pressures over multiple treatments indicate outflow stenosis, which can be confirmed with access flow studies or fistulogram.

Question 65: Which complication is characterized by swelling of the entire arm on the side of an AV access?

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

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 66: Proper labeling of a reprocessed dialyzer must include:

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

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

Low-flux cellulose acetate
Unmodified cellulose
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 68: Vascular access care bundles in hemodialysis facilities are designed primarily to reduce:

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

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 69: After removing hemodialysis needles, how long should manual pressure typically be held to achieve hemostasis on an AVF?

30 minutes minimum
1-2 minutes
30 seconds
5-15 minutes (Correct answer)

Correct answer: 5-15 minutes

Manual pressure of 5-15 minutes is typically required after needle removal from an AVF to achieve adequate hemostasis without compromising the access.

Question 70: Activated clotting time (ACT) monitoring during dialysis is used to:

Guide heparin dosing to prevent clotting without over-anticoagulating (Correct answer)
Measure dialysis adequacy in real time
Assess the patient's hemoglobin level
Determine the correct ultrafiltration rate

Correct answer: Guide heparin dosing to prevent clotting without over-anticoagulating

ACT measures how long blood takes to clot and guides heparin titration to maintain adequate anticoagulation throughout the treatment.

Question 71: 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)
Pre-dialysis sample drawn 5 minutes after starting the blood pump
Post-dialysis sample drawn 30 minutes after treatment ends
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 72: A tunneled dialysis catheter is locked with which solution between dialysis sessions to maintain patency?

Heparin or citrate locking solution (Correct answer)
Tissue plasminogen activator (tPA)
Antibiotic solution
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 73: The Kt/V adequacy target for hemodialysis patients according to KDOQI guidelines is a minimum of:

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

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 74: The 'buttonhole' or constant-site cannulation technique involves:

Using a new site every treatment
Rotating between three sites
Only using the arterial needle
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 75: When dialyzing a patient with active pulmonary tuberculosis, which additional precaution is required beyond standard precautions?

Airborne precautions with N95 respirator and negative-pressure room if available (Correct answer)
Contact precautions only
No additional precautions beyond standard
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 76: What is the normal oxygen saturation (SpO2) range for a healthy adult as measured by pulse oximetry?

90–94%
95–100% (Correct answer)
75–85%
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 77: What does the term 'high-flux dialysis' refer to?

Use of very high blood flow rates above 500 mL/min
Dialysis performed more than 3 times per week
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 78: Which bloodborne pathogen is most commonly transmitted in hemodialysis units due to shared equipment and environmental contamination?

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

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 79: One body part's water can be transferred to another by:

all of the above
osmotic forces (Correct answer)
ultrafiltration
active transport

Correct answer: osmotic forces

Water moves from one body fluid compartment to another according to osmotic forces. During hemodialysis, water is pushed through the membrane by ultrafiltration to reduce the blood's solute concentration. Because the concentration of cellular osmotically active solutes is now higher than that in the blood, water is then returned to the cells and tissues from the blood via osmotic pressures. Hypotension and a drop in blood volume could arise from this. It is possible to add sodium to the dialysate, which will raise the blood's osmolality and cause the cells and tissues to lose water. Later on in the dialysis procedure, the salt content of the dialysate is reduced to enable the removal of more water from the blood. Later on in the dialysis procedure, the salt content of the dialysate is reduced to enable the removal of more water from the blood. The dialyzer experiences ultrafiltration, whereas the bodily compartments do not. Ion exchange across cellular membranes may be driven by active transport, although water flow is passive and controlled by osmotic pressures.

Question 80: The maximum number of times a dialyzer may be reused is determined by:

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

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

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

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

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

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 83: The immediate action when air embolism is suspected during hemodialysis is:

Flush with normal saline immediately
Increase blood flow rate to push air through
Clamp the venous line, stop the blood pump, and position patient in left lateral Trendelenburg (Correct answer)
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 84: Hemolysis during hemodialysis can be caused by:

Low blood flow rate below 200 mL/min
Kinked blood tubing or excessive blood pump speed (Correct answer)
High dialysate bicarbonate
High transmembrane pressure

Correct answer: Kinked blood tubing or excessive blood pump speed

Mechanical destruction of red blood cells can occur due to kinked tubing, stenotic needles, or excessively high pump speeds creating shear stress.

Question 85: When using a tunneled hemodialysis catheter, the recommended locking solution placed in the catheter lumens between treatments is:

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

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

solvent drag
adsorption
convection
diffusion (Correct answer)

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

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

Correct answer: Activated carbon tank

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

Question 88: During hemodialysis, the venous pressure alarm goes high and the blood pump stops. The first action the technician should take is:

Increase the blood pump speed to overcome the resistance
Immediately remove the venous needle
Administer a saline bolus to the patient
Clamp the venous line and check for kinks or occlusion (Correct answer)

Correct answer: Clamp the venous line and check for kinks or occlusion

A high venous pressure alarm indicates downstream resistance; clamping and inspecting the venous line for kinks or clotted segments is the correct initial response.

Question 89: After reprocessing, dialyzers must be stored at what temperature to maintain germicide efficacy?

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

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

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

Correct answer: 34:1

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

Question 91: Which medication is used to reverse heparin anticoagulation in cases of bleeding during hemodialysis?

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

Correct answer: Protamine sulfate

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

Question 92: 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)
Elevated potassium levels
Hypertension and weight gain
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 93: 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 94: Which electrolyte imbalance is most commonly treated with sodium bicarbonate supplementation in dialysis patients?

Hyperphosphatemia
Hyperkalemia
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 95: The reverse osmosis (RO) unit in water treatment works primarily by:

Ion exchange
UV irradiation
Adsorption
Forcing water through a semi-permeable membrane under pressure (Correct answer)

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

Reverse osmosis forces water under pressure through a semi-permeable membrane, rejecting dissolved contaminants and producing purified water.

Question 96: Which method is used to estimate the weekly standard Kt/V (stdKt/V) for comparing different dialysis schedules?

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

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

1500–2000 mL
700–1000 mL
300–500 mL (Correct answer)
100–200 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 98: 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 99: 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)
Hypovolemia from ultrafiltration
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 100: When manually cleaning a dialyzer during reprocessing, water used for rinsing must meet which standard?

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

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

Calcium carbonate (Correct answer)
Aluminum hydroxide
Sevelamer
Lanthanum carbonate

Correct answer: Calcium carbonate

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

Question 102: What is the maximum allowable level of chloramine in dialysis water according to AAMI standards?

0.5 mg/L
0.1 mg/L (Correct answer)
2.0 mg/L
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 103: Increasing which treatment parameter is the most effective way to improve Kt/V in a hemodialysis patient?

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

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

Only patients under age 40
Only staff, not patients
All susceptible (anti-HBs negative) hemodialysis patients (Correct answer)
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 105: Which vital sign measurement is MOST important to obtain before initiating each hemodialysis treatment?

Pulse oximetry only
Temperature 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 106: Before cannulating a patient's arteriovenous fistula, which assessment must ALWAYS be performed first?

Inspect and palpate the access site for thrill, bruit, redness, swelling, and pain (Correct answer)
Irrigate the fistula site with heparinized saline solution
Measure blood pressure in the arm that contains the fistula
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 107: When a patient with a synthetic AV graft requires needle insertion, the technician should rotate needle sites to prevent:

Thrombosis at the arterial anastomosis
Aneurysmal dilation from repeated cannulation in the same area (Correct answer)
Infection spreading along the graft material
Hematoma formation at insertion points

Correct answer: Aneurysmal dilation from repeated cannulation in the same area

Repeated needle insertion at the same site in a graft causes localized weakness and aneurysm formation, so rotating sites (rope-ladder or buttonhole techniques) is essential.

Question 108: An AV fistula thrill that is absent on palpation and a bruit that is absent on auscultation most likely indicates:

Access thrombosis (Correct answer)
High cardiac output state
Normal fistula maturation
Excellent access function

Correct answer: Access thrombosis

Loss of palpable thrill and audible bruit in a previously functioning AVF is a classic sign of thrombosis requiring urgent intervention.

Question 109: What does KUF (ultrafiltration coefficient) measure in a dialyzer?

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

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

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

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

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

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 112: The following are referred to as the "sieving coefficient of a membrane":

fraction of solute that passes through the membrane by convection. (Correct answer)
size of the pores in the membrane.
amount of water required for solute drag through the membrane.
concentration of pores in the membrane.

Correct answer: fraction of solute that passes through the membrane by convection.

Convection, the movement of water from the blood to the dialysate through the membrane, is accompanied by solvent drag, the movement of molecules. The proportion of a solute that is transported by convection depends on the size of the molecule as well as the size and quantity of membrane pores. Large molecules move more slowly while small molecules move freely and swiftly. The amount of a specific solute that flows through the membrane from the blood into the dialysate is referred to as the ""sieving coefficient of a membrane."" A sieving value of 1.0 means that 100% of a given solute passed through the membrane by a convective mechanism, whereas a sieving coefficient of 0.4 means that only 40% of a given solute did so.

Question 113: The maximum recommended ultrafiltration rate to minimize intradialytic hypotension and cardiovascular stress is:

5 mL/kg/hour
13 mL/kg/hour (Correct answer)
20 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 114: What is a patient's 'dry weight' in the context of hemodialysis?

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

Post-BUN ÷ Pre-BUN × 100
(Post-BUN − Pre-BUN) ÷ Post-BUN × 100
(Pre-BUN − Post-BUN) ÷ Pre-BUN × 100 (Correct answer)
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 116: Which class of medications is most commonly used to treat anemia in dialysis patients?

Granulocyte colony-stimulating factors
Vitamin B12 injections
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 117: 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?

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

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

13–17 mS/cm (Correct answer)
2–4 mS/cm
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 119: Which action is required before each dialysis treatment to verify proper blood pathway integrity?

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

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 120: A patient's dialysis adequacy lab results show a URR of 58%. According to KDOQI, this result indicates:

Excellent dialysis adequacy exceeding target
Inadequate dialysis requiring intervention (Correct answer)
Normal variation not requiring adjustment
Adequate dialysis meeting minimum standards

Correct answer: Inadequate dialysis requiring intervention

KDOQI recommends a minimum URR of 65%; a URR of 58% is below target and indicates inadequate urea reduction, requiring assessment of treatment parameters.

Question 121: What is the purpose of the dialysate bypass system on a hemodialysis machine?

Route dialysate past the dialyzer when an alarm condition is detected (Correct answer)
Recirculate used dialysate
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 122: Which of the following dialysis access types typically provides the highest blood flow rates and lowest infection risk?

Synthetic AV graft
Tunneled cuffed catheter
Native AV fistula (Correct answer)
Temporary non-tunneled catheter

Correct answer: Native AV fistula

A native AV fistula provides the highest flow rates, best long-term patency, and lowest infection rates of all dialysis access types.

Question 123: What is the recommended minimum treatment time for a thrice-weekly hemodialysis session?

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

Correct answer: 3 hours

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

Question 124: A patient's fistula has a bruit that is continuous and high-pitched throughout systole and diastole. This is:

Normal — indicates good blood flow through the access (Correct answer)
Normal only if present at the anastomosis
Abnormal — indicates steal syndrome
Abnormal — indicates thrombosis

Correct answer: Normal — indicates good blood flow through the access

A continuous, soft, low-pitched bruit heard throughout the cardiac cycle indicates a well-functioning AVF with adequate blood flow.

Question 125: A thrill that is weak or absent at the AV fistula site most likely indicates:

Successful maturation
Infiltration of the access
Stenosis or thrombosis of the fistula (Correct answer)
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 126: Dialysis steal syndrome occurs when:

The access clots repeatedly
Venous pressures exceed 250 mmHg
The patient experiences hypotension
Too much blood flows through the access, reducing distal limb perfusion (Correct answer)

Correct answer: Too much blood flows through the access, reducing distal limb perfusion

Steal syndrome occurs when arterial blood is diverted preferentially into the AVF/graft, reducing perfusion to the hand and causing ischemia.

Question 127: 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)
Dialysate flow rate calibration
Ultrafiltration controller accuracy

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 128: Hemolysis during dialysis can be identified by which characteristic change in the venous blood line?

Bright pink or cherry-red discoloration of blood (Correct answer)
Dark, burgundy-colored blood
Formation of white fibrin strands
Visible air bubbles in the blood

Correct answer: Bright pink or cherry-red discoloration of blood

Hemolysis causes red blood cells to rupture, releasing hemoglobin and turning the blood bright pink or cherry-red (port wine color).

Question 129: When disconnecting a patient at the end of hemodialysis, the blood is returned to the patient using:

Normal saline rinse-back through the arterial line (Correct answer)
Heparinized normal saline pushed rapidly
Hypertonic saline to maximize fluid return
Air pushed through the venous line to clear the tubing

Correct answer: Normal saline rinse-back through the arterial line

Blood is returned at treatment end by infusing normal saline through the arterial line, pushing blood from the circuit back to the patient through the venous line.

Question 130: 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 131: 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)
Using antibiotic ointment on all exit sites routinely
Only cleaning the exit site monthly
Cleaning only with normal saline, no dressing required

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

Patients with known or suspected prion disease (CJD) (Correct answer)
Diabetic patients
HIV-positive patients only
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 133: Which medication is commonly used to treat hypotension during hemodialysis?

Midodrine (Correct answer)
Captopril
Furosemide
Metoprolol

Correct answer: Midodrine

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

Question 134: Before a reprocessed dialyzer is used on a patient, residual germicide must be tested. Which test confirms formaldehyde removal?

Glucose oxidase strip
Colorimetric test using chromotropic acid or equivalent (Correct answer)
Conductivity test
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 135: Which organism is the most common cause of catheter-related bloodstream infections in hemodialysis patients?

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

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

Venous needle kinking
Inadequate blood flow from the access (Correct answer)
Access recirculation
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 137: Which chemical is most commonly used as a germicide in manual dialyzer reprocessing?

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

Correct answer: Formaldehyde (4%)

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

Question 138: A dialysis patient taking calcium carbonate as a phosphate binder should be instructed to take it:

After dialysis sessions only
At bedtime
With meals to bind dietary phosphate (Correct answer)
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 139: Kayexalate (sodium polystyrene sulfonate) is used in dialysis patients to manage which condition?

Metabolic acidosis
Hyperphosphatemia
Hypercalcemia
Hyperkalemia (Correct answer)

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

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

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

Increase the UFR to compensate for fluid infiltration
Inject heparin at the site
Remove the needle, apply pressure, and assess the site (Correct answer)
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 142: After completing hemodialysis, a patient's post-treatment weight should ideally match which reference value?

The patient's body weight at the time dialysis therapy was first initiated
The patient's established dry weight (target weight) (Correct answer)
The average weight of demographically similar dialysis patients
The patient's weight recorded one month prior

Correct answer: The patient's established dry weight (target weight)

Post-dialysis weight should equal the patient's established dry weight, confirming that appropriate fluid removal was achieved without over- or under-ultrafiltration.

Question 143: What is the generally recommended maximum ultrafiltration rate to reduce the risk of intradialytic hypotension?

Less than 5 mL/kg/hour
Less than 13 mL/kg/hour (Correct answer)
Greater than 20 mL/kg/hour
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 144: What does a consistently falling pre-dialysis BUN suggest about a patient's dialysis prescription or status?

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

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 145: 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 146: Which chemical is most commonly used to disinfect the dialysis water distribution loop?

Bleach only
Isopropyl alcohol
Peracetic acid (Correct answer)
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 147: Which practice is PROHIBITED in dialysis treatment areas to prevent cross-contamination between patients?

Using individual patient supply packs
Using dedicated carts for medication administration
Wearing gloves for needle removal
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 148: A dialysis patient has a pre-BUN of 80 mg/dL and a post-BUN of 20 mg/dL. What is the URR?

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

Correct answer: 75%

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

Question 149: What is the primary concern when administering EPO (erythropoietin) to a dialysis patient with uncontrolled hypertension?

EPO can further increase blood pressure and risk of stroke (Correct answer)
EPO is ineffective in hypertensive patients
EPO depletes iron stores faster in hypertension
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 150: Which sign indicates that a patient may be experiencing steal syndrome from an AV access?

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

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 151: 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.

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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