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

Question 1: A biomedical technician measures 150 microamperes of chassis leakage current on a hemodialysis machine. What is the appropriate action?

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

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

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

Question 2: What is the 'reject water' from a reverse osmosis system?

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

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

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

Question 3: Under CMS ESRD regulations, who is responsible for ensuring the dialysis prescription is appropriate and orders are updated?

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

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

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

Question 4: A dialysis patient is diagnosed with active pulmonary tuberculosis (TB). What isolation precautions are required?

Droplet precautions: surgical mask for staff within 3 feet of the patient
Contact precautions only: gown and gloves for all patient interactions
Airborne precautions: N95 respirator for staff, negative pressure room, and patient to wear surgical mask when outside their room (Correct answer)
Standard precautions are sufficient since dialysis patients are already immunocompromised

Correct answer: Airborne precautions: N95 respirator for staff, negative pressure room, and patient to wear surgical mask when outside their room

Pulmonary TB requires airborne precautions because M. tuberculosis is transmitted by airborne droplet nuclei. An N95 (or higher) respirator must be worn by staff, and a negative pressure isolation room is required. Dialysis units must have an emergency protocol for TB patients.

Question 5: Which practice is MOST effective at preventing cross-contamination between hemodialysis patients?

Wearing the same gloves for all patients
Consistent hand hygiene between each patient contact (Correct answer)
Using alcohol spray on gloves instead of changing them
Cleaning surfaces weekly

Correct answer: Consistent hand hygiene between each patient contact

Hand hygiene remains the single most effective infection control measure for preventing patient-to-patient transmission of pathogens in healthcare settings.

Question 6: Which regulatory standard requires dialysis facilities to have a written emergency preparedness plan?

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

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

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

Question 7: All of the following substances are produced by the kidney EXCEPT:

renin.
erythropoietin.
aldosterone. (Correct answer)
calcitriol.

Correct answer: aldosterone.

The kidneys produce several important substances, including renin (for blood pressure regulation), erythropoietin (for red blood cell production), and calcitriol (the active form of vitamin D). Aldosterone, however, is a hormone produced by the adrenal glands, not the kidneys, and plays a role in regulating sodium and potassium balance.

Question 8: Why should blood pressure never be measured in the arm containing an arteriovenous fistula?

Blood pressure measurement is prohibited in any arm with a chronic wound
Cuff compression can restrict fistula blood flow and potentially cause thrombosis (Correct answer)
The bruit creates noise that interferes with Korotkoff sounds, giving inaccurate readings
The fistula creates artificially elevated pressures due to high flow

Correct answer: Cuff compression can restrict fistula blood flow and potentially cause thrombosis

BP cuff inflation compresses the fistula, interrupting high-volume flow and risking thrombosis. Additionally, venipuncture, IV lines, and tight clothing are also contraindicated in the fistula arm.

Question 9: The most common cause of chronic kidney disease in the United States is:

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

Correct answer: diabetes.

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

Question 10: What is the typical sodium concentration range in hemodialysis dialysate?

150–165 mEq/L
120–130 mEq/L
100–115 mEq/L
135–145 mEq/L (Correct answer)

Correct answer: 135–145 mEq/L

Dialysate sodium is typically maintained at 135–145 mEq/L to approximate normal plasma sodium and avoid hypo- or hypernatremia during treatment.

Question 11: Which type of electrical isolation transformer provides the safest power for patient-connected medical equipment in a dialysis unit?

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

Correct answer: Medical-grade isolation transformer

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

Question 12: During a power failure in a dialysis unit, which component of the electrical system is designed to provide immediate backup power to hemodialysis machines without interruption?

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

Correct answer: Uninterruptible power supply (UPS)

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

Question 13: How should a dialysis technician handle a machine that has been used by an HCV-positive patient?

Follow standard machine disinfection protocols — no special additional procedures are required beyond standard precautions (Correct answer)
Remove the machine from service permanently
Use higher-concentration disinfectant only
Quarantine the machine for 24 hours

Correct answer: Follow standard machine disinfection protocols — no special additional procedures are required beyond standard precautions

HCV is not efficiently transmitted via the dialysate pathway, so standard disinfection protocols are sufficient; dedicated machines are required only for HBsAg-positive patients.

Question 14: The fluid restriction for most patients undergoing in-center hemodialysis is equal to urine volume/day plus:

0 L.
0.5 L.
1 L. (Correct answer)
2 L.

Correct answer: 1 L.

For most in-center hemodialysis patients, a common fluid restriction guideline is to limit daily fluid intake to their residual urine output plus 1 liter. This additional liter accounts for insensible fluid losses (e.g., through breathing and sweat) and helps prevent excessive fluid accumulation between dialysis sessions.

Question 15: How often should a dialysis technician perform a visual check of the extracorporeal blood circuit during treatment?

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

Correct answer: At least every 30 minutes throughout the treatment

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

Question 16: What is the primary goal of tracking machine-specific adverse event rates in a dialysis quality program?

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

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

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

Question 17: According to AAMI TIR No. 12, what is the recommended maximum resistance for the protective earth (ground) conductor in patient-connected medical equipment?

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

Correct answer: 0.1 ohm

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

Question 18: Which condition is described as calcification of blood vessels and soft tissues caused by an elevated calcium-phosphate product in ESRD?

Amyloidosis
Metastatic calcification
Beta-2 microglobulin deposition
Calciphylaxis (Correct answer)

Correct answer: Calciphylaxis

Calciphylaxis is a serious, often fatal complication in ESRD patients characterized by vascular calcification and skin necrosis driven by disordered mineral metabolism.

Question 19: Why must the hemodialysis machine alarm be checked if blood appears in the dialysate effluent?

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

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

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

Question 20: What is the correct method for testing ground wire integrity on hemodialysis equipment using a biomedical safety analyzer?

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

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

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

Question 21: Why is the arterial needle typically inserted in the direction of blood flow (toward the heart) in an AVF?

Because the venous needle must face away from the heart per ESRD regulations
To allow the arterial needle to draw blood from the direction of highest flow for optimal pump function (Correct answer)
To prevent turbulence that causes hemolysis in the needle
To reduce the risk of infiltration by following the vessel anatomy

Correct answer: To allow the arterial needle to draw blood from the direction of highest flow for optimal pump function

For AVF, the arterial needle is typically placed antegrade (with flow, toward the heart) or retrograde depending on facility protocol and access anatomy. The goal is to separate arterial and venous needles by at least 3–5 cm to minimize recirculation.

Question 22: Which ion in dialysate is primarily responsible for controlling dialysate conductivity?

Bicarbonate
Calcium
Sodium (Correct answer)
Potassium

Correct answer: Sodium

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

Question 23: Heparin resistance in a dialysis patient is most commonly associated with:

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

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

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

Question 24: How frequently should dialysis station surfaces be disinfected between patients?

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

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

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

Question 25: What concentration of dialysate potassium is typically used for patients with pre-dialysis serum potassium above 6.0 mEq/L?

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

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

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

Question 26: After using heat disinfection on a dialysis machine, the technician must verify the machine is safe for the next patient by:

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

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

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

Question 27: An occupational exposure report for a dialysis technician involved in a needlestick from a patient with unknown HIV status should include:

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

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

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

Question 28: Which NFPA standard specifically governs electrical safety requirements in health care facilities, including dialysis units?

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

Correct answer: NFPA 99

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

Question 29: What is the primary purpose of equipotential bonding in a hemodialysis patient care area?

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

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

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

Certified Hemodialysis Bio-Medical Technician (CHBT)

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

150

Questions

180 min

Time Limit

70%

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