IAHCSMM Sterilization Methods & Monitoring 1 — Questions and Answers
Question 1: What is the standard steam sterilization cycle temperature and minimum exposure time for wrapped instruments at prevacuum?
- 121°C (250°F) for 30 minutes
- 132°C (270°F) for 4 minutes
- 134°C (273°F) for 4 minutes (Correct answer)
- 121°C (250°F) for 15 minutes
Correct answer: 134°C (273°F) for 4 minutes
AAMI ST79 recommends 134°C for 4 minutes as the standard prevacuum (dynamic air removal) cycle for wrapped loads.
Question 2: What is the primary advantage of ethylene oxide (EO) sterilization over steam sterilization?
- Faster cycle times
- Lower cost per cycle
- Ability to sterilize heat- and moisture-sensitive devices (Correct answer)
- No aeration period required
Correct answer: Ability to sterilize heat- and moisture-sensitive devices
EO operates at low temperatures and low humidity, making it suitable for heat- and moisture-sensitive instruments that cannot withstand steam.
Question 3: Which biological indicator (BI) organism is used to test the efficacy of steam sterilization?
- Bacillus atrophaeus (B. atrophaeus)
- Geobacillus stearothermophilus (G. stearothermophilus) (Correct answer)
- Clostridium botulinum
- Staphylococcus aureus
Correct answer: Geobacillus stearothermophilus (G. stearothermophilus)
Geobacillus stearothermophilus spores are highly resistant to moist heat and are the standard BI for steam sterilization monitoring.
Question 4: A Bowie-Dick test is performed to verify:
- Biological indicator kill rate
- Adequate air removal in prevacuum steam sterilizers (Correct answer)
- Chemical indicator color change consistency
- EO gas penetration in chambers
Correct answer: Adequate air removal in prevacuum steam sterilizers
The Bowie-Dick test (or air removal test) detects residual air pockets that prevent steam penetration in dynamic air-removal sterilizers.
Question 5: How long should a positive biological indicator result be investigated before releasing a recalled load?
- The load should be recalled immediately upon any positive BI result (Correct answer)
- Wait 24 hours then re-test
- Wait for two consecutive negative results before releasing
- Only recall if three consecutive positive results occur
Correct answer: The load should be recalled immediately upon any positive BI result
A positive BI result requires immediate load recall and investigation per AAMI ST79 protocols to ensure patient safety.
Question 6: What is the minimum aeration time required for EO-sterilized items at room temperature (ambient aeration)?
- 4 hours
- 8 hours
- 12 hours
- 7 days (Correct answer)
Correct answer: 7 days
EO ambient aeration at room temperature requires 7 days to allow residual gas to off-gas to safe levels for patient contact.
IAHCSMM Sterilization Methods & Monitoring 1
What is the standard steam sterilization cycle temperature and minimum exposure time for wrapped instruments at prevacuum?