AAMI ST79 & TIR12 COMPREHENSIVE EXAM STUDY GUIDE: 150+ VERIFIED QUESTIONS
WITH RATIONALES (LATEST UPDATE)
SECTION A: STEAM STERILIZATION FUNDAMENTALS AND PARAMETERS
1. What is the minimum exposure time, temperature, and pressure required for sterilization
in a pre-vacuum steam sterilizer for wrapped instrument trays?
A. 3 minutes at 270°F (132°C) and 27 psi
B. 4 minutes at 270°F (132°C) and 28–30 psi
C. 15 minutes at 250°F (121°C) and 15 psi
D. 30 minutes at 250°F (121°C) and 15 psi
Rationale: According to AAMI standards, wrapped instrument trays processed in a pre-
vacuum steam sterilizer must be exposed for a minimum of 4 minutes at 270°F (132°C)
with a chamber pressure of 28 to 30 psi to ensure complete steam penetration and
microbial destruction. Gravity-displacement cycles require longer times because air
removal is passive rather than mechanically forced.
2. Which of the following monitoring tools is designed specifically to detect air leaks,
inadequate air removal, and non-condensable gases in the chamber of a pre-vacuum
steam sterilizer?
A. Class 5 Integrating Indicator
B. Class 6 Emulating Indicator
C. Bowie-Dick Test
D. Biological Indicator containing Geobacillus stearothermophilus
,Rationale: The Bowie-Dick test is a dynamic air removal test specifically designed for pre-
vacuum sterilizers to detect air leaks, inadequate air removal, and non-condensable gases.
It must be performed daily, in an empty chamber, before the first processed load.
3. Which biological indicator organism is used to monitor steam sterilization cycles?
A. Bacillus atrophaeus spores
B. Geobacillus stearothermophilus spores
C. Bacillus subtilis spores
D. Clostridium sporogenes spores
Rationale: Geobacillus stearothermophilus spores are the biological indicator of choice for
steam sterilization because of their high resistance to moist heat. Bacillus atrophaeus
spores are utilized to monitor dry heat and ethylene oxide sterilization.
4. When double-pouching surgical instruments using paper-plastic peel pouches, which
orientation rules must be strictly followed?
A. Plastic faces plastic, and the inner pouch must be tightly folded over
B. Paper faces plastic, and the inner pouch must not be folded or sealed at all
C. Paper faces paper, and both pouches must be sealed independently without folding
the inner pouch
D. Plastic faces paper, and the inner pouch must be folded over to fit snugly
Rationale: When double-pouching, items must be placed paper-to-paper to allow proper
air removal and steam penetration, and both pouches must be sealed independently.
Folding the inner pouch can create barriers to sterilization.
5. What is the minimum exposure time and temperature for a gravity-displacement steam
sterilizer cycle for wrapped items?
A. 3 minutes at 270°F (132°C)
B. 4 minutes at 270°F (132°C)
C. 30 minutes at 250°F (121°C)
D. 15 minutes at 250°F (121°C)
Rationale: Gravity-displacement cycles require longer exposure times because air removal
relies on passive displacement rather than mechanical vacuum. The standard minimum for
wrapped items is 30 minutes at 250°F (121°C) with a pressure of 15 psi.
,6. Which of the following is NOT one of the four critically interdependent phases that
provide the framework for ANSI/AAMI ST79?
A. Lowering and limiting bioburden before sterilization
B. Properly preparing items for sterilization
C. Selecting the least expensive packaging materials
D. Establishing and implementing controls to maintain sterility until use
Rationale: The four phases are: 1) lowering and limiting bioburden, 2) properly preparing
items, 3) selecting appropriate sterilization parameters, and 4) establishing controls to
maintain sterility. Cost considerations are not a foundational phase of the standard.
7. What is the maximum acceptable residual moisture level on instruments after steam
sterilization?
A. 1%
B. 0% (no visible moisture)
C. 5%
D. 3%
Rationale: AAMI ST79 requires that items be dry upon removal from the sterilizer. Any
visible moisture indicates a drying failure that could compromise the sterile barrier and
lead to contamination.
8. Which of the following packaging materials is NOT appropriate for steam sterilization?
A. Medical-grade paper
B. Non-woven polypropylene (unless specifically rated for steam)
C. Muslin fabric (140 thread count)
D. Rigid sterilization container systems
Rationale: Non-woven polypropylene packaging must be specifically validated for steam
sterilization. Standard non-woven wraps may not withstand steam penetration and drying
requirements.
9. What is the primary purpose of a Class 5 integrating indicator?
A. To detect air leaks in the sterilizer chamber
B. To respond to all critical parameters of the sterilization process (time, temperature,
, and steam quality)
C. To indicate whether an item has been exposed to ethylene oxide
D. To replace biological indicators entirely
Rationale: Class 5 integrating indicators are designed to react to all critical parameters of
the sterilization process and are intended to be equivalent to, or exceed, the performance
of a biological indicator.
10. Which of the following conditions would require immediate use steam sterilization
(IUSS)?
A. Routine processing of wrapped instrument trays
B. A dropped instrument during a surgical procedure with no replacement available
C. Planned sterilization of implants before surgery
D. Terminal sterilization of reusable devices
Rationale: IUSS is intended for urgent, unplanned situations where a critical item is
contaminated and no alternative is immediately available. It should never be used for
convenience or routine processing.
SECTION B: STERILE PROCESSING FACILITY DESIGN AND PERSONNEL
11. In sterile processing department (SPD) design, what is the correct workflow direction to
prevent cross-contamination?
A. Clean to sterile to decontamination
B. Decontamination to preparation to sterilization to sterile storage
C. Sterile storage to decontamination to preparation
D. Preparation to decontamination to sterilization
Rationale: The correct workflow moves from dirty to clean to sterile. This one-way traffic
pattern prevents clean and sterile items from being exposed to contaminated items.
12. What is the minimum recommended air exchange rate for the decontamination area in
a sterile processing department?
A. 2 air exchanges per hour
B. 6 air exchanges per hour
C. 10 air exchanges per hour
D. 15 air exchanges per hour
WITH RATIONALES (LATEST UPDATE)
SECTION A: STEAM STERILIZATION FUNDAMENTALS AND PARAMETERS
1. What is the minimum exposure time, temperature, and pressure required for sterilization
in a pre-vacuum steam sterilizer for wrapped instrument trays?
A. 3 minutes at 270°F (132°C) and 27 psi
B. 4 minutes at 270°F (132°C) and 28–30 psi
C. 15 minutes at 250°F (121°C) and 15 psi
D. 30 minutes at 250°F (121°C) and 15 psi
Rationale: According to AAMI standards, wrapped instrument trays processed in a pre-
vacuum steam sterilizer must be exposed for a minimum of 4 minutes at 270°F (132°C)
with a chamber pressure of 28 to 30 psi to ensure complete steam penetration and
microbial destruction. Gravity-displacement cycles require longer times because air
removal is passive rather than mechanically forced.
2. Which of the following monitoring tools is designed specifically to detect air leaks,
inadequate air removal, and non-condensable gases in the chamber of a pre-vacuum
steam sterilizer?
A. Class 5 Integrating Indicator
B. Class 6 Emulating Indicator
C. Bowie-Dick Test
D. Biological Indicator containing Geobacillus stearothermophilus
,Rationale: The Bowie-Dick test is a dynamic air removal test specifically designed for pre-
vacuum sterilizers to detect air leaks, inadequate air removal, and non-condensable gases.
It must be performed daily, in an empty chamber, before the first processed load.
3. Which biological indicator organism is used to monitor steam sterilization cycles?
A. Bacillus atrophaeus spores
B. Geobacillus stearothermophilus spores
C. Bacillus subtilis spores
D. Clostridium sporogenes spores
Rationale: Geobacillus stearothermophilus spores are the biological indicator of choice for
steam sterilization because of their high resistance to moist heat. Bacillus atrophaeus
spores are utilized to monitor dry heat and ethylene oxide sterilization.
4. When double-pouching surgical instruments using paper-plastic peel pouches, which
orientation rules must be strictly followed?
A. Plastic faces plastic, and the inner pouch must be tightly folded over
B. Paper faces plastic, and the inner pouch must not be folded or sealed at all
C. Paper faces paper, and both pouches must be sealed independently without folding
the inner pouch
D. Plastic faces paper, and the inner pouch must be folded over to fit snugly
Rationale: When double-pouching, items must be placed paper-to-paper to allow proper
air removal and steam penetration, and both pouches must be sealed independently.
Folding the inner pouch can create barriers to sterilization.
5. What is the minimum exposure time and temperature for a gravity-displacement steam
sterilizer cycle for wrapped items?
A. 3 minutes at 270°F (132°C)
B. 4 minutes at 270°F (132°C)
C. 30 minutes at 250°F (121°C)
D. 15 minutes at 250°F (121°C)
Rationale: Gravity-displacement cycles require longer exposure times because air removal
relies on passive displacement rather than mechanical vacuum. The standard minimum for
wrapped items is 30 minutes at 250°F (121°C) with a pressure of 15 psi.
,6. Which of the following is NOT one of the four critically interdependent phases that
provide the framework for ANSI/AAMI ST79?
A. Lowering and limiting bioburden before sterilization
B. Properly preparing items for sterilization
C. Selecting the least expensive packaging materials
D. Establishing and implementing controls to maintain sterility until use
Rationale: The four phases are: 1) lowering and limiting bioburden, 2) properly preparing
items, 3) selecting appropriate sterilization parameters, and 4) establishing controls to
maintain sterility. Cost considerations are not a foundational phase of the standard.
7. What is the maximum acceptable residual moisture level on instruments after steam
sterilization?
A. 1%
B. 0% (no visible moisture)
C. 5%
D. 3%
Rationale: AAMI ST79 requires that items be dry upon removal from the sterilizer. Any
visible moisture indicates a drying failure that could compromise the sterile barrier and
lead to contamination.
8. Which of the following packaging materials is NOT appropriate for steam sterilization?
A. Medical-grade paper
B. Non-woven polypropylene (unless specifically rated for steam)
C. Muslin fabric (140 thread count)
D. Rigid sterilization container systems
Rationale: Non-woven polypropylene packaging must be specifically validated for steam
sterilization. Standard non-woven wraps may not withstand steam penetration and drying
requirements.
9. What is the primary purpose of a Class 5 integrating indicator?
A. To detect air leaks in the sterilizer chamber
B. To respond to all critical parameters of the sterilization process (time, temperature,
, and steam quality)
C. To indicate whether an item has been exposed to ethylene oxide
D. To replace biological indicators entirely
Rationale: Class 5 integrating indicators are designed to react to all critical parameters of
the sterilization process and are intended to be equivalent to, or exceed, the performance
of a biological indicator.
10. Which of the following conditions would require immediate use steam sterilization
(IUSS)?
A. Routine processing of wrapped instrument trays
B. A dropped instrument during a surgical procedure with no replacement available
C. Planned sterilization of implants before surgery
D. Terminal sterilization of reusable devices
Rationale: IUSS is intended for urgent, unplanned situations where a critical item is
contaminated and no alternative is immediately available. It should never be used for
convenience or routine processing.
SECTION B: STERILE PROCESSING FACILITY DESIGN AND PERSONNEL
11. In sterile processing department (SPD) design, what is the correct workflow direction to
prevent cross-contamination?
A. Clean to sterile to decontamination
B. Decontamination to preparation to sterilization to sterile storage
C. Sterile storage to decontamination to preparation
D. Preparation to decontamination to sterilization
Rationale: The correct workflow moves from dirty to clean to sterile. This one-way traffic
pattern prevents clean and sterile items from being exposed to contaminated items.
12. What is the minimum recommended air exchange rate for the decontamination area in
a sterile processing department?
A. 2 air exchanges per hour
B. 6 air exchanges per hour
C. 10 air exchanges per hour
D. 15 air exchanges per hour
