CRCST Sterilization Methods 3 — Questions and Answers
Question 1: What is the purpose of the Bowie-Dick test in steam sterilization?
- To confirm biological indicator kill
- To verify air removal and steam penetration in prevacuum sterilizers (Correct answer)
- To measure sterilant concentration
- To test package seal integrity
Correct answer: To verify air removal and steam penetration in prevacuum sterilizers
The Bowie-Dick test verifies adequate air removal and uniform steam penetration in prevacuum (dynamic air removal) steam sterilizers.
Question 2: Low-temperature sterilization using ozone works primarily through which mechanism?
- Protein alkylation
- Oxidation of cellular components (Correct answer)
- Lipid peroxidation of membranes only
- DNA cross-linking via UV activation
Correct answer: Oxidation of cellular components
Ozone sterilization destroys microorganisms through oxidation of cellular components including proteins, lipids, and nucleic acids.
Question 3: The sterilization assurance level (SAL) for medical devices is defined as a probability of not more than:
- 1 in 100
- 1 in 1,000
- 1 in 10,000
- 1 in 1,000,000 (Correct answer)
Correct answer: 1 in 1,000,000
The SAL for sterile medical devices is 10⁻⁶, meaning no more than a 1 in 1,000,000 chance of a viable microorganism remaining.
Question 4: Which type of chemical indicator changes color based on exposure to specific sterilization parameters?
- Class 1 — process indicators
- Class 3 — single-variable indicators
- Class 5 — integrating indicators (Correct answer)
- Class 6 — emulating indicators
Correct answer: Class 5 — integrating indicators
Class 5 integrating indicators react to all critical parameters (time, temperature, and sterilant) and are designed to correlate with biological indicator performance.
Question 5: What minimum aeration time is typically required after EtO sterilization at ambient room temperature (20°C)?
- 4 hours
- 8 hours
- 12 hours
- 7 days (Correct answer)
Correct answer: 7 days
At room temperature (20°C), EtO-sterilized items require approximately 7 days of aeration to reduce residual EtO to safe levels.
Question 6: Which statement correctly describes the difference between sterilization and disinfection?
- Sterilization kills all bacteria; disinfection kills only fungi
- Sterilization destroys all forms of microbial life; disinfection reduces but may not eliminate all microorganisms (Correct answer)
- Disinfection is required before sterilization can be performed
- Sterilization applies only to liquids; disinfection applies to surfaces
Correct answer: Sterilization destroys all forms of microbial life; disinfection reduces but may not eliminate all microorganisms
Sterilization destroys all forms of microbial life including spores, while disinfection reduces microbial counts but may not eliminate all forms.
Question 7: Formaldehyde-based low-temperature sterilization is classified as which level of germicide?
- High-level disinfectant only
- Intermediate-level disinfectant
- Sporicide and sterilant (Correct answer)
- Low-level disinfectant
Correct answer: Sporicide and sterilant
Formaldehyde at appropriate concentrations and exposure times is classified as a sporicide and sterilant capable of achieving sterilization.
CRCST Sterilization Methods 3
What is the purpose of the Bowie-Dick test in steam sterilization?