Certified Hemodialysis Technologist/Technician Exam Dialysis Adequacy and Prescription 1 — Questions and Answers
Question 1: What does the term 'Kt/V' measure in hemodialysis adequacy?
- Ultrafiltration rate relative to body weight
- Dose of dialysis delivered, representing urea clearance relative to urea volume of distribution (Correct answer)
- Time on dialysis divided by volume of dialysate used
- Blood flow rate times treatment time
Correct answer: Dose of dialysis delivered, representing urea clearance relative to urea volume of distribution
Kt/V is a dimensionless index of dialysis adequacy where K = dialyzer clearance, t = treatment time, and V = volume of distribution of urea.
Question 2: What is the minimum single-pool Kt/V (spKt/V) recommended by KDOQI for thrice-weekly hemodialysis?
- 1.0
- 1.2 (Correct answer)
- 1.4
- 1.6
Correct answer: 1.2
KDOQI guidelines recommend a minimum spKt/V of 1.2 per session for patients on thrice-weekly hemodialysis.
Question 3: URR (urea reduction ratio) is calculated as:
- (Pre-BUN − Post-BUN) ÷ Pre-BUN × 100 (Correct answer)
- Post-BUN ÷ Pre-BUN × 100
- Pre-BUN ÷ Post-BUN × 100
- (Post-BUN − 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 4: A minimum URR of what percentage is recommended for adequate hemodialysis?
- 45%
- 55%
- 65% (Correct answer)
- 75%
Correct answer: 65%
A URR of at least 65% is the recommended minimum for adequate dialysis, correlating with a Kt/V of approximately 1.2.
Question 5: Which blood sample timing is critical for accurate Kt/V calculation?
- Pre-dialysis sample drawn 5 minutes after starting the blood pump
- Post-dialysis sample drawn immediately after stopping the blood pump with a slow-flow technique (Correct answer)
- 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 6: Increasing which treatment parameter is the most effective way to improve Kt/V in a hemodialysis patient?
- Dialysate sodium concentration
- Treatment time (Correct answer)
- Ultrafiltration volume
- Heparin dose
Correct answer: Treatment time
Extending treatment time is the most effective single intervention for improving Kt/V because it directly increases the 't' component.
Certified Hemodialysis Technologist/Technician Exam Dialysis Adequacy and Prescription 1
What does the term 'Kt/V' measure in hemodialysis adequacy?