IAHCSMM CRCST 2026
COMPREHENSIVE EXAMINATION
QUESTIONS AND ANSWERS
1. Which of the following describes the correct sequence for the cycle of a dynamic-air-
removal steam sterilizer?
A. Air removal, Steam injection, Exposure, Cooling
B. Pre-vacuum, Exposure, Exhaust, Drying
C. Conditioning, Sterilization, Exhaust, Drying
D. Conditioning, Exposure, Exhaust, Aeration
Answer: C
Conceptual Explanation: The four phases of a dynamic-air-removal steam cycle are
conditioning (where air is removed and steam is injected), sterilization (exposure at
temperature), exhaust, and drying.
2. According to Spaulding’s classification of medical devices, a colonoscope is considered
which of the following?
A. Critical
B. Non-critical
,C. Semi-critical
D. Intermediate-critical
Answer: C
Conceptual Explanation: Semi-critical items are those that come into contact with mucous
membranes or non-intact skin and require high-level disinfection.
3. In the decontamination area, the relative humidity should be maintained within what
range?
A. 30% to 60%
B. 20% to 50%
C. 40% to 70%
D. 10% to 30%
Answer: A
Conceptual Explanation: ANSI/AAMI ST79 recommends maintaining relative humidity in
the decontamination area between 30% and 60% to inhibit microbial growth and ensure
staff comfort.
4. Which organism is the most resistant to the sterilization process and used in Biological
Indicators for steam sterilization?
A. Mycobacterium tuberculosis
B. Bacillus atrophaeus
, C. Geobacillus stearothermophilus
D. Staphylococcus aureus
Answer: C
Conceptual Explanation: Geobacillus stearothermophilus spores are highly resistant to
heat and are the standard biological challenge for steam and hydrogen peroxide
sterilization.
5. What is the minimum exposure time for a gravity-displacement steam sterilization cycle at
250°F (121°C)?
A. 30 minutes
B. 10 minutes
C. 15 minutes
D. 4 minutes
Answer: A
Conceptual Explanation: Gravity-displacement cycles at 250°F require a minimum of 30
minutes of exposure to ensure lethality.
6. The process by which ultrasonic cleaners clean instruments is known as:
A. Impingement
B. Oxidation
C. Electrolysis
COMPREHENSIVE EXAMINATION
QUESTIONS AND ANSWERS
1. Which of the following describes the correct sequence for the cycle of a dynamic-air-
removal steam sterilizer?
A. Air removal, Steam injection, Exposure, Cooling
B. Pre-vacuum, Exposure, Exhaust, Drying
C. Conditioning, Sterilization, Exhaust, Drying
D. Conditioning, Exposure, Exhaust, Aeration
Answer: C
Conceptual Explanation: The four phases of a dynamic-air-removal steam cycle are
conditioning (where air is removed and steam is injected), sterilization (exposure at
temperature), exhaust, and drying.
2. According to Spaulding’s classification of medical devices, a colonoscope is considered
which of the following?
A. Critical
B. Non-critical
,C. Semi-critical
D. Intermediate-critical
Answer: C
Conceptual Explanation: Semi-critical items are those that come into contact with mucous
membranes or non-intact skin and require high-level disinfection.
3. In the decontamination area, the relative humidity should be maintained within what
range?
A. 30% to 60%
B. 20% to 50%
C. 40% to 70%
D. 10% to 30%
Answer: A
Conceptual Explanation: ANSI/AAMI ST79 recommends maintaining relative humidity in
the decontamination area between 30% and 60% to inhibit microbial growth and ensure
staff comfort.
4. Which organism is the most resistant to the sterilization process and used in Biological
Indicators for steam sterilization?
A. Mycobacterium tuberculosis
B. Bacillus atrophaeus
, C. Geobacillus stearothermophilus
D. Staphylococcus aureus
Answer: C
Conceptual Explanation: Geobacillus stearothermophilus spores are highly resistant to
heat and are the standard biological challenge for steam and hydrogen peroxide
sterilization.
5. What is the minimum exposure time for a gravity-displacement steam sterilization cycle at
250°F (121°C)?
A. 30 minutes
B. 10 minutes
C. 15 minutes
D. 4 minutes
Answer: A
Conceptual Explanation: Gravity-displacement cycles at 250°F require a minimum of 30
minutes of exposure to ensure lethality.
6. The process by which ultrasonic cleaners clean instruments is known as:
A. Impingement
B. Oxidation
C. Electrolysis
