CER High-Level Disinfection Processes 4 — Questions and Answers
Question 1: What happens to the reuse life of an HLD solution when it is diluted by repeatedly immersing wet endoscopes?
- The reuse life is extended because water stabilizes the chemical
- The concentration drops and reuse life is shortened (Correct answer)
- Dilution has no effect if the temperature remains constant
- The solution becomes more effective at lower concentrations
Correct answer: The concentration drops and reuse life is shortened
Water introduced by wet scopes dilutes the HLD solution, lowering its concentration and potentially shortening the time it remains above the minimum required concentration.
Question 2: According to AAMI ST91, what type of water should be used for the final rinse of a high-level disinfected endoscope?
- Tap water filtered to 0.2 microns or sterile water (Correct answer)
- Standard tap water at room temperature
- Distilled water heated to 60°C
- Tap water with added enzymatic detergent
Correct answer: Tap water filtered to 0.2 microns or sterile water
AAMI ST91 recommends sterile water or water filtered through a 0.2-micron filter for the final rinse to prevent recontamination of the scope.
Question 3: Which of the following conditions would require discarding an HLD solution before its labeled reuse date?
- The solution temperature rises above 25°C briefly
- The MRC test strip indicates concentration is below the minimum (Correct answer)
- The container lid was left off for less than 30 minutes
- A new lot of test strips was opened
Correct answer: The MRC test strip indicates concentration is below the minimum
If the MRC test indicates the solution has fallen below minimum required concentration, it must be discarded immediately regardless of the reuse date.
Question 4: A gastroscope used on a patient with active tuberculosis requires which level of reprocessing?
- Standard precaution cleaning only
- Low-level disinfection with 70% alcohol
- High-level disinfection following standard reprocessing protocol (Correct answer)
- Immediate disposal as single-use equipment
Correct answer: High-level disinfection following standard reprocessing protocol
Mycobacterium tuberculosis is susceptible to high-level disinfectants, so standard HLD reprocessing protocol is appropriate and sufficient for this organism.
Question 5: What is the recommended approach when an endoscope cannot be reprocessed immediately after patient use?
- Store the scope dry in a cabinet until the next morning
- Keep it submerged in water to prevent drying of secretions
- Perform pre-cleaning immediately and place it in enzymatic solution or dry transport (Correct answer)
- Wrap it in a sterile drape and refrigerate
Correct answer: Perform pre-cleaning immediately and place it in enzymatic solution or dry transport
Pre-cleaning at point of use followed by transport in enzymatic solution or dry transport to the reprocessing area prevents biofilm formation and protects staff.
Question 6: How should HLD chemicals be stored to maintain their stability?
- In a warm area above 30°C to enhance activity
- According to manufacturer instructions, typically cool and away from light (Correct answer)
- Mixed with enzymatic detergents to extend shelf life
- In open containers to allow off-gassing of harmful vapors
Correct answer: According to manufacturer instructions, typically cool and away from light
HLD chemicals should be stored per manufacturer instructions, generally in cool, dark areas, to prevent premature degradation and maintain labeled potency.
Question 7: Which organization sets national guidelines specifically addressing endoscope reprocessing and HLD in the United States?
- CDC and AAMI, through guidelines such as ST91 (Correct answer)
- OSHA, through the Bloodborne Pathogens Standard only
- The Joint Commission, through accreditation surveys only
- The FDA, through 510(k) clearance of scopes
Correct answer: CDC and AAMI, through guidelines such as ST91
The CDC and AAMI (through standard ST91) provide the primary national guidelines for endoscope reprocessing, including HLD procedures, in the United States.
CER High-Level Disinfection Processes 4
What happens to the reuse life of an HLD solution when it is diluted by repeatedly immersing wet endoscopes?