CRCST Instrument Processing 2 — Questions and Answers
Question 1: Which enzyme is most commonly used in enzymatic detergents to break down protein-based bioburden on surgical instruments?
- Lipase
- Protease (Correct answer)
- Amylase
- Cellulase
Correct answer: Protease
Protease enzymes specifically break down proteins, which constitute the majority of blood and tissue soils on surgical instruments.
Question 2: During mechanical decontamination in a washer-disinfector, what temperature range is typically used in the thermal disinfection cycle to achieve pasteurization?
- 55–60°C (131–140°F)
- 71–80°C (160–176°F) (Correct answer)
- 93–100°C (199–212°F)
- 121–134°C (250–273°F)
Correct answer: 71–80°C (160–176°F)
Thermal disinfection in washer-disinfectors typically uses 71–80°C for a specified time to achieve pasteurization-level disinfection.
Question 3: A hinged instrument is opened before sterilization primarily to:
- Prevent the ratchet from locking during cooling
- Allow steam or sterilant contact on all surfaces including box locks (Correct answer)
- Reduce the weight load on the sterilization tray
- Prevent instrument tips from touching each other
Correct answer: Allow steam or sterilant contact on all surfaces including box locks
Opening hinged instruments ensures sterilant reaches the box lock area, which is a critical contact point that cannot be penetrated when the instrument is closed.
Question 4: Which of the following best describes 'critical' items in the Spaulding Classification System?
- Items that contact intact skin and require disinfection
- Items that contact mucous membranes and require high-level disinfection
- Items that enter sterile tissue or the vascular system and require sterilization (Correct answer)
- Items used in the environment that require low-level disinfection
Correct answer: Items that enter sterile tissue or the vascular system and require sterilization
Critical items enter sterile body tissue or the vascular system and pose the highest infection risk, requiring sterilization before use.
Question 5: What is the purpose of a biological indicator (BI) in sterilization monitoring?
- To verify the sterilizer chamber reached the correct temperature
- To confirm that packaging integrity was maintained during the cycle
- To demonstrate that viable microorganisms were killed during the sterilization process (Correct answer)
- To measure residual moisture in the sterilized load
Correct answer: To demonstrate that viable microorganisms were killed during the sterilization process
Biological indicators contain highly resistant spores; their destruction after processing confirms the sterilization process was effective at killing microorganisms.
Question 6: When using ultrasonic cleaners, cavitation refers to:
- The formation and collapse of microscopic bubbles that dislodge soil (Correct answer)
- The heating of water to remove protein bioburden
- The use of high-pressure jets to flush instrument lumens
- The chemical reaction between detergent and organic matter
Correct answer: The formation and collapse of microscopic bubbles that dislodge soil
Cavitation is the rapid formation and implosion of tiny bubbles created by high-frequency sound waves, which physically dislodge soil from instrument surfaces.
Question 7: Which sterilization method is most appropriate for moisture-sensitive, heat-sensitive instruments such as flexible endoscopes?
- Steam sterilization at 132°C
- Dry heat sterilization
- Ethylene oxide (EO) gas sterilization (Correct answer)
- Flash sterilization (IUSS)
Correct answer: Ethylene oxide (EO) gas sterilization
Ethylene oxide sterilization uses low temperatures and is appropriate for heat- and moisture-sensitive instruments that cannot withstand steam.
CRCST Instrument Processing 2
Which enzyme is most commonly used in enzymatic detergents to break down protein-based bioburden on surgical instruments?