100+ Free CHBT Practice Questions

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Question 1

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A water softener in a dialysis facility primarily removes:

Dissolved organic compounds

Calcium and magnesium ions

Bacteria and endotoxins

Chlorine and chloramines

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2026 Statistics

Key Facts: CHBT Exam

150

Exam Questions

3-hour limit

$235

Exam Fee

BONENT 2026

4 years

Recertification Cycle

BONENT

0.1 mg/L

Chloramine Maximum

AAMI/ISO 23500

100 CFU/mL

Bacteria Maximum

AAMI/ISO 23500

0.5 EU/mL

Endotoxin Maximum

AAMI/ISO 23500

The BONENT CHBT exam contains 150 questions over 3 hours. Content focuses on dialysis machine biomedical systems, water treatment per AAMI/ISO 23500, preventive maintenance, disinfection, alarm troubleshooting, and regulatory compliance. Eligibility requires documented experience in hemodialysis equipment maintenance. Recertification is every 4 years.

Sample CHBT Practice Questions

Try these sample questions to test your CHBT exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A dialysis machine's conductivity meter reads 15.2 mS/cm when the target is 14.0 mS/cm. Which component is most likely responsible?

A.Defective blood pump

B.Proportioning pump delivering excess acid concentrate

C.Air detector sensor failure

D.Venous pressure transducer drift

Explanation: Conductivity reflects dissolved solute concentration in dialysate. Excess acid concentrate increases ion content, raising conductivity above target. The proportioning pump ratio must be verified and recalibrated.

2According to AAMI/ANSI 23500, the maximum allowable chloramine level in water used to prepare dialysate is:

A.0.5 mg/L

B.0.1 mg/L

C.1.0 mg/L

D.0.25 mg/L

Explanation: AAMI/ISO 23500 sets the maximum chloramine limit at 0.1 mg/L (100 µg/L) in product water. Chloramines cause hemolysis and methemoglobinemia and must be removed by two carbon tanks in series.

3A technician is performing a 10-minute carbon tank contact time test. The test comes back positive for chloramine. The FIRST corrective action is to:

A.Replace the RO membranes

B.Switch to deionization for water treatment

C.Perform a 30-minute contact time test on the downstream carbon tank

D.Immediately take all machines off-line and notify the charge nurse

Explanation: A positive chloramine test means product water is unsafe. Immediate patient-risk mitigation requires taking machines offline and notifying clinical staff before any further diagnostic testing.

4The AAMI/ISO 23500 maximum bacterial colony-forming unit (CFU) limit for standard dialysate is:

A.200 CFU/mL

B.100 CFU/mL

C.50 CFU/mL

D.500 CFU/mL

Explanation: AAMI/ISO 23500 specifies a maximum of 100 CFU/mL for standard dialysis water, with an action level of 50 CFU/mL prompting remedial steps before the maximum is reached.

5The endotoxin action level for dialysis water per AAMI/ISO 23500 is:

A.0.25 EU/mL

B.1.0 EU/mL

C.2.0 EU/mL

D.0.5 EU/mL

Explanation: The AAMI/ISO 23500 endotoxin action level is 0.25 EU/mL for standard dialysis water; the maximum is 0.5 EU/mL. Reaching the action level triggers investigation and corrective steps before the maximum is breached.

6Transmembrane pressure (TMP) is calculated as:

A.Arterial inlet pressure minus venous outlet pressure

B.Mean blood compartment pressure minus dialysate compartment pressure

C.Venous pressure minus arterial pressure

D.Dialysate inlet pressure minus blood inlet pressure

Explanation: TMP = [(arterial blood pressure + venous blood pressure)/2] − dialysate pressure. It drives ultrafiltration across the dialyzer membrane; excessive TMP can cause membrane rupture.

7A blood leak alarm activates during treatment. The FIRST step the biomedical technician should take is to:

A.Replace the blood leak detector

B.Verify the alarm with a dipstick test on dialysate effluent

C.Immediately clamp the blood lines and end treatment

D.Increase the dialysate flow rate

Explanation: A false blood leak alarm is common. A dipstick or orthotoluidine test on effluent dialysate confirms whether true hemoglobin leakage is occurring before clinical action is taken.

8Which component of the dialysis water treatment system is responsible for removing particulate matter and sediment?

A.Reverse osmosis membrane

B.Multimedia filter

C.Carbon adsorption tank

D.Ultrafilter

Explanation: The multimedia filter (sand/anthracite/gravel) is the first-stage mechanical filtration step, removing turbidity and particulate matter that would foul downstream components.

9A water softener in a dialysis facility primarily removes:

A.Chlorine and chloramines

B.Dissolved organic compounds

C.Calcium and magnesium ions

D.Bacteria and endotoxins

Explanation: Water softeners use ion-exchange resin (sodium form) to replace hardness ions (Ca²⁺, Mg²⁺) with sodium, protecting RO membranes from scale buildup.

10RO membrane rejection rate is calculated as:

A.(Permeate TDS / Feed TDS) × 100

B.[(Feed TDS − Permeate TDS) / Feed TDS] × 100

C.(Feed TDS − Concentrate TDS) × 100

D.(Permeate flow / Feed flow) × 100

Explanation: % Rejection = [(Feed TDS − Permeate TDS) / Feed TDS] × 100. A properly functioning dialysis RO unit should achieve ≥95% rejection of dissolved solids.

About the CHBT Exam

The CHBT certification validates technical proficiency in hemodialysis biomedical equipment maintenance. The 150-question exam covers dialysis machine systems, water treatment (AAMI/ISO 23500), machine disinfection, preventive maintenance, alarm troubleshooting, electrical safety, and CMS/regulatory compliance. Offered in paper-and-pencil format by BONENT.

Questions

150 scored questions

Time Limit

3 hours

Passing Score

Scaled passing score (BONENT cut score)

Exam Fee

$235 (BONENT (Board of Nephrology Examiners Nursing and Technology))

CHBT Exam Content Outline

~30%

Dialysis Machine Systems

Blood circuit, hydraulic/dialysate circuit, proportioning pumps, conductivity/temperature calibration, air detector, blood leak detector, venous/arterial/transmembrane pressure monitoring, UF control

~28%

Water Treatment Systems

Multimedia filter, carbon adsorption tanks (chloramine testing), water softener, RO (rejection rate, membrane cleaning), DI, UV, ultrafilters, AAMI/ISO 23500 chemical/bacteriological/endotoxin limits, action vs. maximum levels

~20%

Machine Maintenance & Disinfection

Preventive maintenance schedules, chemical disinfection (bleach, peracetic acid, citric acid), heat disinfection, residual testing, alarm functional tests, pressure hold, UF accuracy verification

~13%

Regulatory, Safety & Documentation

CMS Conditions for Coverage (42 CFR §494.40), FDA (21 CFR Part 820), OSHA bloodborne pathogen standard, electrical safety (leakage current, GFCI, ground continuity), maintenance documentation

~9%

Concentrate Systems & Dialyzer Reuse

Acid and bicarbonate concentrate management, proportioning verification, dialyzer reuse (Renalin, TCV ≥80%), concentrate contamination risks

How to Pass the CHBT Exam

What You Need to Know

Passing score: Scaled passing score (BONENT cut score)
Exam length: 150 questions
Time limit: 3 hours
Exam fee: $235

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

CHBT Study Tips from Top Performers

1Memorize AAMI/ISO 23500 limits: chloramine ≤0.1 mg/L, bacteria ≤100 CFU/mL (action 50), endotoxin ≤0.5 EU/mL (action 0.25)

2Understand the water treatment component sequence: multimedia filter → softener → carbon tanks (×2) → RO → DI/UV → ultrafilter

3Know daily carbon tank testing requirements: 10-minute and 30-minute contact time chloramine breakthrough tests

4Practice TMP and RO rejection rate calculations

5Understand dialysate bypass mode triggers: conductivity or temperature out-of-range

6Know disinfectant residual testing methods: OT/DPD for bleach, PAA test strip for peracetic acid

7Review CMS 42 CFR §494.40 requirements for water quality documentation and monthly testing

8Study electrical safety limits: chassis leakage ≤100 µA, ground resistance ≤0.5 Ω

9Understand the role of each proportioning pump in conductivity control

10Know TCV ≥80% original volume requirement for dialyzer reuse

Frequently Asked Questions

What is the BONENT CHBT certification?

The CHBT (Certified Hemodialysis Biomedical Technician) is a specialty certification from BONENT (Board of Nephrology Examiners Nursing and Technology). It validates technical competency in dialysis equipment maintenance, water treatment, preventive maintenance, alarm troubleshooting, and regulatory compliance for hemodialysis biomedical technicians.

How many questions are on the CHBT exam?

The BONENT CHBT exam contains 150 multiple-choice questions with a 3-hour time limit. It is administered in paper-and-pencil format at BONENT-approved testing events.

What are the CHBT eligibility requirements?

Eligibility requires documented work experience in hemodialysis biomedical/equipment maintenance per BONENT requirements. Applicants must submit an application with supporting documentation. See the BONENT Candidate Handbook at bonent.org for current requirements.

What content areas does the CHBT exam cover?

The CHBT exam covers dialysis machine systems (blood and dialysate circuits, proportioning, alarms), water treatment (multimedia filters, carbon tanks, softeners, RO, DI, AAMI/ISO 23500 standards), machine disinfection and preventive maintenance, electrical safety, and CMS/regulatory compliance.

How long is CHBT certification valid?

CHBT certification is valid for 4 years. Recertification requires 40 CEUs (minimum 30 Group A hours) or retaking the BONENT examination. Documentation must be submitted within 30 days of the expiration date.

What is the CHBT exam fee?

The BONENT CHBT exam fee is $235. Candidates must submit a new application and fee for retakes.

How should I prepare for the CHBT exam?

Study the BONENT CHBT Content Outline (available at bonent.org), AAMI/ISO 23500 water quality standards, CMS ESRD Conditions for Coverage (42 CFR §494.40), dialysis machine service manuals, and OSHA bloodborne pathogen regulations. Focus heavily on water treatment chemistry, proportioning systems, alarm troubleshooting, and electrical safety. Plan for 8-14 weeks of preparation.