CIC Cleaning, Disinfection, & Sterilization 4 — Questions and Answers
Question 1: Which action should an infection preventionist recommend when a sterilizer fails its biological indicator (BI) test?
- Continue using the sterilizer and retest with a second BI
- Remove the sterilizer from service and recall items from the failed load (Correct answer)
- Increase the sterilization cycle temperature for future loads
- Notify administration only if more than three BI failures occur
Correct answer: Remove the sterilizer from service and recall items from the failed load
A failed BI requires immediate removal of the sterilizer from service and recall of items from the failed load per AAMI and CDC guidelines.
Question 2: The term 'log reduction' in disinfection refers to:
- The volume of disinfectant used per square foot
- A tenfold reduction in the number of viable organisms (Correct answer)
- The time required to kill 100% of organisms
- The pH change that occurs during disinfection
Correct answer: A tenfold reduction in the number of viable organisms
Each log reduction represents a 10-fold (90%) decrease in microbial count; a 6-log reduction eliminates 99.9999% of organisms.
Question 3: Which of the following is the correct order of reprocessing steps for a reusable semi-critical medical device?
- Disinfect → Clean → Rinse → Dry → Store
- Clean → Rinse → Disinfect → Rinse → Dry → Store (Correct answer)
- Rinse → Disinfect → Clean → Dry → Store
- Clean → Disinfect → Rinse → Store without drying
Correct answer: Clean → Rinse → Disinfect → Rinse → Dry → Store
Proper reprocessing sequence is: clean, rinse, high-level disinfect, rinse with sterile or filtered water, dry, then store in a protected manner.
Question 4: Which practice is recommended to prevent biofilm formation in endoscope channels between reprocessing steps?
- Soaking the endoscope in tap water
- Flushing channels with air and alcohol immediately after each procedure (Correct answer)
- Storing endoscopes in the original manufacturer shipping case
- Immersing endoscopes in low-level disinfectant
Correct answer: Flushing channels with air and alcohol immediately after each procedure
Immediate flushing of endoscope channels with air followed by 70% alcohol prevents biofilm formation and speeds drying before full reprocessing.
Question 5: What does the 'D-value' represent in sterilization science?
- The dose of radiation needed to kill all organisms
- The time required to reduce organism count by 90% under specific conditions (Correct answer)
- The distance between sterilizer heating elements
- The dilution factor for disinfectant preparation
Correct answer: The time required to reduce organism count by 90% under specific conditions
The D-value (decimal reduction time) is the time required under defined conditions to reduce the microbial population by one log (90%).
Question 6: According to CDC guidelines, how long should flexible endoscopes be stored after high-level disinfection before they must be reprocessed again (if unused)?
- 24 hours
- 48 hours
- 5–7 days (facility policy-based) (Correct answer)
- 30 days
Correct answer: 5–7 days (facility policy-based)
CDC and professional societies recommend that storage duration be based on facility policy, typically 5–7 days, provided the endoscope is stored dry in a ventilated cabinet.
Question 7: Which chemical class is classified as an intermediate-level disinfectant and is effective against Mycobacterium tuberculosis?
- Quaternary ammonium compounds (quats)
- 70–90% isopropyl or ethyl alcohol (Correct answer)
- Hypochlorites at 10 ppm
- Benzalkonium chloride
Correct answer: 70–90% isopropyl or ethyl alcohol
Alcohols (70–90%) are intermediate-level disinfectants with tuberculocidal activity, making them appropriate for surfaces and non-critical equipment.
CIC Cleaning, Disinfection, & Sterilization 4
Which action should an infection preventionist recommend when a sterilizer fails its biological indicator (BI) test?