IAHCSMM (CRCST) EXAM 2026/2027
COMPREHENSIVE MASTER REVIEW
1. The D-value for a specific microorganism represents:
A. The temperature needed to kill a specific population of microorganisms
B. The time in minutes to reduce a microbial population by 90% at a specific temperature
C. The depth of penetration required for steam to reach the center of a pack
D. The duration of aeration required after ethylene oxide sterilization
Answer: B
Conceptual Explanation: The D-value (Decimal Reduction Value) is the time required, at a
specific temperature, to kill 90% of the microorganisms in a sample.
2. Which of the following stainless steel series is non-magnetic and highly resistant to
corrosion?
A. 400 series
B. 500 series
C. 200 series
,D. 300 series
Answer: D
Conceptual Explanation: 300 series stainless steel (austenitic) is non-magnetic and offers
high corrosion resistance, commonly used for retractors and basins.
3. In the decontamination area, the ventilation system should maintain:
A. Positive pressure with 10 air exchanges per hour
B. Positive pressure with 20 air exchanges per hour
C. Negative pressure with 10 air exchanges per hour
D. Negative pressure with 4 air exchanges per hour
Answer: C
Conceptual Explanation: AAMI ST79 standards require the decontamination area to be
under negative pressure to prevent the spread of contaminants, with a minimum of 10 air
exchanges per hour.
4. Which type of sterilization process is incompatible with cellulose-based materials like
paper and cotton?
A. Hydrogen peroxide gas plasma
B. Pre-vacuum steam
C. Gravity displacement steam
D. Ethylene oxide
, Answer: A
Conceptual Explanation: Hydrogen peroxide gas plasma (H2O2) is absorbed by cellulose
(paper/cotton), which causes the cycle to abort; synthetic wraps must be used instead.
5. What is the correct temperature and humidity requirement for the sterile storage area?
A. 75°F (24°C) and 70% humidity
B. 60-65°F (16-18°C) and 30-60% humidity
C. Up to 75°F (24°C) and humidity not exceeding 70%
D. 72°F (22°C) and exactly 50% humidity
Answer: C
Conceptual Explanation: Sterile storage should be kept at a temperature not exceeding
75°F (24°C) and a relative humidity not exceeding 70% to prevent microbial growth and
package degradation.
6. The process by which ultrasonic cleaners remove soil is called:
A. Impingement
B. Cavitation
C. Ionization
D. Ozonation
Answer: B
COMPREHENSIVE MASTER REVIEW
1. The D-value for a specific microorganism represents:
A. The temperature needed to kill a specific population of microorganisms
B. The time in minutes to reduce a microbial population by 90% at a specific temperature
C. The depth of penetration required for steam to reach the center of a pack
D. The duration of aeration required after ethylene oxide sterilization
Answer: B
Conceptual Explanation: The D-value (Decimal Reduction Value) is the time required, at a
specific temperature, to kill 90% of the microorganisms in a sample.
2. Which of the following stainless steel series is non-magnetic and highly resistant to
corrosion?
A. 400 series
B. 500 series
C. 200 series
,D. 300 series
Answer: D
Conceptual Explanation: 300 series stainless steel (austenitic) is non-magnetic and offers
high corrosion resistance, commonly used for retractors and basins.
3. In the decontamination area, the ventilation system should maintain:
A. Positive pressure with 10 air exchanges per hour
B. Positive pressure with 20 air exchanges per hour
C. Negative pressure with 10 air exchanges per hour
D. Negative pressure with 4 air exchanges per hour
Answer: C
Conceptual Explanation: AAMI ST79 standards require the decontamination area to be
under negative pressure to prevent the spread of contaminants, with a minimum of 10 air
exchanges per hour.
4. Which type of sterilization process is incompatible with cellulose-based materials like
paper and cotton?
A. Hydrogen peroxide gas plasma
B. Pre-vacuum steam
C. Gravity displacement steam
D. Ethylene oxide
, Answer: A
Conceptual Explanation: Hydrogen peroxide gas plasma (H2O2) is absorbed by cellulose
(paper/cotton), which causes the cycle to abort; synthetic wraps must be used instead.
5. What is the correct temperature and humidity requirement for the sterile storage area?
A. 75°F (24°C) and 70% humidity
B. 60-65°F (16-18°C) and 30-60% humidity
C. Up to 75°F (24°C) and humidity not exceeding 70%
D. 72°F (22°C) and exactly 50% humidity
Answer: C
Conceptual Explanation: Sterile storage should be kept at a temperature not exceeding
75°F (24°C) and a relative humidity not exceeding 70% to prevent microbial growth and
package degradation.
6. The process by which ultrasonic cleaners remove soil is called:
A. Impingement
B. Cavitation
C. Ionization
D. Ozonation
Answer: B
