✅ Total Chlorine & Free Chlorine in Dialysis Water – MCQs (Set 1)
1. What is the maximum allowable level of total chlorine in dialysis water as per AAMI standards?
A. 0.1 mg/L
B. 0.5 mg/L
C. 0.3 mg/L
D. 1.0 mg/L
➡️ Answer: C. 0.1 mg/L
2. Which form of chlorine is more harmful to patients during hemodialysis?
A. Free chlorine
B. Total chlorine
C. Chloramine
D. Chloride
➡️ Answer: C. Chloramine
(Chloramines can cause hemolysis in dialysis patients)
3. Total chlorine is the sum of which of the following?
A. Free chlorine only
B. Free chlorine + combined chlorine (chloramines)
C. Chloride and chlorate
D. Free chlorine + chloride
➡️ Answer: B. Free chlorine + combined chlorine (chloramines)
4. Which of the following is used to test total chlorine in dialysis settings?
A. pH meter
B. Amperometric sensor
C. Colorimetric test strips (DPD test)
D. TDS meter
➡️ Answer: C. Colorimetric test strips (DPD test)
5. If total chlorine levels exceed the allowable limit in dialysis water, what should be done?
A. Increase dialysate flow
B. Shut down dialysis immediately
C. Notify patients to increase fluid intake
D. Continue dialysis with higher ultrafiltration
➡️ Answer: B. Shut down dialysis immediately
(And investigate the carbon filter performance)
6. What is the recommended action if free chlorine is 0.2 mg/L but total chlorine is 0.4 mg/L?
A. Continue dialysis as normal
B. Switch to backup water source
C. Replace carbon filters or cartridges
D. Add sodium hypochlorite
➡️ Answer: C. Replace carbon filters or cartridges
7. What is the most effective method for removing chlorine and chloramines from dialysis water?
A. Reverse osmosis membrane
B. UV sterilization
C. Carbon filtration
D. Ultrafiltration
➡️ Answer: C. Carbon filtration
8. Chloramine levels in dialysis water should be below:
A. 0.1 mg/L
B. 0.3 mg/L
C. 0.01 mg/L
D. 0.5 mg/L
➡️ Answer: A. 0.1 mg/L
9. Why is monitoring of total chlorine important in dialysis?
A. To reduce sodium in water
B. To avoid reverse osmosis membrane fouling
C. To prevent patient hemolysis
D. To maintain water temperature
➡️ Answer: C. To prevent patient hemolysis
10. Free chlorine reacts with ammonia to form which harmful compound?
A. Chloride
B. Chloramine
C. Fluoride
D. Bromate
➡️ Answer: B. Chloramine
11. What is the most frequent cause of elevated total chlorine levels in dialysis water systems?
A. Reverse osmosis failure
B. Poor maintenance of UV light
C. Exhausted carbon filter
D. Broken conductivity sensor
➡️ Answer: C. Exhausted carbon filter
12. Which point in the water treatment system is typically used for chlorine testing?
A. Before sediment filter
B. After first carbon tank and before second carbon tank
C. After RO unit
D. After ultrafilter
➡️ Answer: B. After first carbon tank and before second carbon tank
(This helps detect breakthrough)
13. The DPD (N,N-diethyl-p-phenylenediamine) test kit is used for:
A. Testing pH only
B. Detecting endotoxins
C. Measuring chlorine (free and total)
D. Testing hardness
➡️ Answer: C. Measuring chlorine (free and total)
14. If total chlorine levels remain high after carbon filtration, the most appropriate next step is to:
A. Flush RO membranes
B. Reduce water pressure
C. Replace carbon beds or cartridges
D. Increase temperature of water
➡️ Answer: C. Replace carbon beds or cartridges
15. Why is chloramine more dangerous than free chlorine in dialysis patients?
A. It leads to electrolyte imbalance
B. It causes systemic hypotension
C. It can pass through carbon filters more easily
D. It causes hemolysis and methemoglobinemia
➡️ Answer: D. It causes hemolysis and methemoglobinemia
16. How often should chlorine levels be tested during dialysis operation?
A. Weekly
B. Every 4 hours
C. Once per shift
D. Before each treatment and every 4 hours during use
➡️ Answer: D. Before each treatment and every 4 hours during use
17. Which of the following statements about free chlorine is TRUE?
A. It is less reactive than chloramines
B. It remains stable longer in water
C. It is quickly neutralized by carbon filtration
D. It cannot cause hemolysis
➡️ Answer: C. It is quickly neutralized by carbon filtration
18. Which factor may reduce the efficiency of carbon filtration in removing chlorine?
A. Low water temperature
B. High water flow rate
C. Acidic pH
D. High TDS
➡️ Answer: B. High water flow rate
(Less contact time with carbon)
19. A high level of chloramine is detected post-carbon filter. What does this indicate?
A. Reverse osmosis malfunction
B. UV disinfection failure
C. Breakthrough of carbon filtration
D. Membrane filter saturation
➡️ Answer: C. Breakthrough of carbon filtration
20. Which of the following actions improves carbon filter performance for chlorine removal?
A. Reducing water temperature
B. Decreasing contact time
C. Using multiple carbon tanks in series
D. Using higher pH water
➡️ Answer: C. Using multiple carbon tanks in series
