MDRAO High-Level Disinfection 2 — Questions and Answers
Question 1: Which of the following is an advantage of orthophthalaldehyde (OPA) over glutaraldehyde for high-level disinfection?
- Shorter required contact time at room temperature
- Less toxic vapor and reduced eye/skin irritation (Correct answer)
- Lower cost per liter
- Effective at lower concentrations for sterilization
Correct answer: Less toxic vapor and reduced eye/skin irritation
OPA has significantly lower vapor pressure than glutaraldehyde, resulting in less odor, fewer respiratory irritant concerns, and reduced need for special ventilation.
Question 2: The minimum recommended contact time for high-level disinfection with 2% glutaraldehyde at 20°C (68°F) is typically:
- 5 minutes
- 10 minutes
- 20 minutes (Correct answer)
- 45 minutes
Correct answer: 20 minutes
At 20°C, a minimum contact time of 20 minutes is required for 2% glutaraldehyde to achieve high-level disinfection.
Question 3: After high-level disinfection, devices must be rinsed thoroughly. What is the PREFERRED rinsing solution?
- Tap water
- Sterile or filtered water (Correct answer)
- Distilled water with detergent
- Isopropyl alcohol solution
Correct answer: Sterile or filtered water
Sterile or filtered water prevents recontamination from waterborne pathogens such as Legionella or Pseudomonas that may be present in tap water.
Question 4: Peracetic acid is often preferred for automated endoscope reprocessors because it:
- Has a longer reuse life than glutaraldehyde
- Does not require rinsing before use
- Is effective at low concentrations with rapid action and low residue (Correct answer)
- Requires no PPE during handling
Correct answer: Is effective at low concentrations with rapid action and low residue
Peracetic acid achieves HLD rapidly, leaves minimal residue, and breaks down into non-toxic byproducts (acetic acid and water), making it well-suited for automated systems.
Question 5: How does elevated temperature affect the efficacy of high-level disinfectant solutions?
- It decreases efficacy by destabilizing the active ingredient
- It has no effect on efficacy
- It increases efficacy, allowing shorter contact times (Correct answer)
- It causes all solutions to exceed sterilization levels automatically
Correct answer: It increases efficacy, allowing shorter contact times
Higher temperatures increase the rate of chemical reactions, enhancing the disinfectant's microbicidal activity and often reducing the required contact time.
Question 6: Biofilm on medical devices is a significant concern for HLD because:
- Biofilm increases device weight, requiring longer immersion
- Biofilm protects embedded microorganisms from chemical disinfectants (Correct answer)
- Biofilm enhances the activity of glutaraldehyde
- Biofilm only forms on critical devices, not semi-critical ones
Correct answer: Biofilm protects embedded microorganisms from chemical disinfectants
Biofilm is a matrix of microorganisms and extracellular material that shields bacteria from disinfectants, making cleaning prior to HLD critical to disrupt and remove it.
Question 7: A device labeled as single-use (SUO) by the manufacturer is presented for high-level disinfection and reuse. What is the correct action?
- Proceed with HLD if the device appears undamaged
- Follow the facility protocol for reprocessing single-use devices
- Do not reprocess; single-use devices must be discarded after use (Correct answer)
- Reprocess only if the device was not in contact with blood
Correct answer: Do not reprocess; single-use devices must be discarded after use
Single-use devices are cleared by regulators for one-time use only; reprocessing them without specific regulatory authorization carries liability and patient safety risks.
MDRAO High-Level Disinfection 2
Which of the following is an advantage of orthophthalaldehyde (OPA) over glutaraldehyde for high-level disinfection?