Certified Hemodialysis Technologist/Technician Exam Dialysis Water Treatment and Quality 2 — Questions and Answers
Question 1: Which bacteria is most commonly associated with dialysis water contamination causing pyrogenic reactions?
- Staphylococcus aureus
- Pseudomonas aeruginosa (Correct answer)
- Escherichia coli
- Streptococcus pyogenes
Correct answer: Pseudomonas aeruginosa
Pseudomonas aeruginosa thrives in water environments and is a leading cause of gram-negative bacteremia and pyrogenic reactions in dialysis patients.
Question 2: What is the AAMI maximum action level for bacterial counts in dialysis water?
- 50 CFU/mL
- 100 CFU/mL (Correct answer)
- 200 CFU/mL
- 500 CFU/mL
Correct answer: 100 CFU/mL
AAMI standards set the action level for bacterial contamination in dialysis water at 100 CFU/mL, requiring corrective action when exceeded.
Question 3: Endotoxin levels in dialysis water should not exceed which AAMI standard?
- 0.1 EU/mL
- 0.25 EU/mL (Correct answer)
- 1 EU/mL
- 5 EU/mL
Correct answer: 0.25 EU/mL
AAMI specifies that endotoxin levels in standard dialysis water must not exceed 0.25 EU/mL to prevent inflammatory reactions.
Question 4: A dialysis technician notices that the RO reject rate has dropped significantly. This most likely indicates:
- The RO membrane is working more efficiently
- RO membrane fouling or failure (Correct answer)
- Improved source water quality
- Softener malfunction only
Correct answer: RO membrane fouling or failure
A drop in RO reject rate (less water being rejected) often signals membrane fouling or failure, reducing its ability to reject contaminants.
Question 5: Which chemical is most commonly used to disinfect the dialysis water distribution loop?
- Isopropyl alcohol
- Peracetic acid (Correct answer)
- Glutaraldehyde
- Bleach only
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 6: The purpose of a UV light unit in a dialysis water treatment system is to:
- Remove heavy metals
- Reduce bacterial load (Correct answer)
- Soften water
- Remove endotoxins
Correct answer: Reduce bacterial load
UV irradiation disrupts bacterial DNA, reducing the bioburden in the water distribution system before it reaches patients.
Certified Hemodialysis Technologist/Technician Exam Dialysis Water Treatment and Quality 2
Which bacteria is most commonly associated with dialysis water contamination causing pyrogenic reactions?