CER Principles and Maintenance 3 — Questions and Answers
Question 1: Which microorganism class is NOT eliminated by high-level disinfection under standard contact conditions?
- Mycobacterium tuberculosis
- Hepatitis B virus
- Clostridium difficile spores in high numbers (Correct answer)
- HIV
Correct answer: Clostridium difficile spores in high numbers
HLD eliminates vegetative bacteria, most fungal spores, viruses, and mycobacteria, but high concentrations of resistant bacterial endospores like C. difficile may survive.
Question 2: What is the correct sequence of manual reprocessing steps for a flexible endoscope?
- Rinse, clean, disinfect, dry
- Pre-clean at bedside, transport, leak test, clean, rinse, HLD, rinse, dry, store (Correct answer)
- Disinfect, clean, rinse, dry, store
- Leak test, transport, disinfect, rinse, dry
Correct answer: Pre-clean at bedside, transport, leak test, clean, rinse, HLD, rinse, dry, store
The validated sequence begins with immediate pre-cleaning at bedside, followed by transport, leak testing, manual cleaning, rinsing, HLD, final rinsing, drying, and storage.
Question 3: Which action should be taken when an endoscope fails a leak test during routine reprocessing?
- Proceed with reprocessing and document the failure for later review
- Remove the scope from service, label it as damaged, and send for repair before reuse (Correct answer)
- Reduce immersion depth to protect the breach
- Increase chemical concentration to compensate for contamination risk
Correct answer: Remove the scope from service, label it as damaged, and send for repair before reuse
A failed leak test means the scope's integrity is compromised; it must be removed from service and repaired before it can be safely reprocessed and used.
Question 4: The term 'bioburden' as it applies to endoscope reprocessing refers to:
- The weight of biological tissue attached to the scope after a procedure
- The number and type of microorganisms present on the endoscope before reprocessing (Correct answer)
- The chemical load of disinfectant absorbed into channels
- The volume of body fluid stored in the elevator channel
Correct answer: The number and type of microorganisms present on the endoscope before reprocessing
Bioburden is the population of viable microorganisms on the endoscope surface and channels that must be reduced through cleaning and disinfection.
Question 5: Which statement best describes the role of enzymatic detergents in endoscope reprocessing?
- They replace the need for mechanical brushing
- They break down proteins, carbohydrates, and lipids to facilitate mechanical removal of bioburden (Correct answer)
- They serve as the primary disinfecting agent
- They neutralize residual glutaraldehyde after HLD
Correct answer: They break down proteins, carbohydrates, and lipids to facilitate mechanical removal of bioburden
Enzymatic detergents contain proteases, amylases, and lipases that chemically digest organic soil, making it easier to remove mechanically during the cleaning phase.
Question 6: Why must all channels of a flexible endoscope be flushed with the cleaning solution during manual reprocessing?
- To check for blockages only
- Because biofilm and debris accumulate inside channels that are inaccessible by brushing alone (Correct answer)
- To warm the scope before disinfection
- To measure channel diameter compliance
Correct answer: Because biofilm and debris accumulate inside channels that are inaccessible by brushing alone
Internal lumens harbor organic material that brushes cannot fully reach; flushing ensures detergent contacts all surfaces to loosen and remove contamination.
Question 7: Personal protective equipment (PPE) required during manual cleaning of endoscopes includes:
- Gloves only
- Fluid-resistant gown, gloves, eye protection, and a surgical mask at minimum (Correct answer)
- A powered air-purifying respirator (PAPR) and double gloves only
- Sterile gown and sterile gloves to prevent contamination of the scope
Correct answer: Fluid-resistant gown, gloves, eye protection, and a surgical mask at minimum
Manual cleaning generates splashing and aerosols from heavily contaminated instruments, requiring full barrier PPE including fluid-resistant gown, gloves, eye/face protection, and mask.
CER Principles and Maintenance 3
Which microorganism class is NOT eliminated by high-level disinfection under standard contact conditions?