CRCST HIGH-LEVEL COMPREHENSIVE
EXAMINATION QUESTIONS AND
ANSWERS
1. Which of the following is the most effective method for removing biofilm from the internal
channels of a flexible endoscope?
A. Soaking in high-level disinfectant for double the recommended time
B. Automated endoscope reprocessor (AER) cycle without manual pre-cleaning
C. Ultrasonic cleaning at 40 kHz
D. Mechanical brushing with a properly sized brush
Answer: D
Conceptual Explanation: Mechanical action (brushing) is the only reliable way to disrupt
and remove the complex matrix of a biofilm from lumens. Disinfectants cannot penetrate
biofilm effectively without mechanical removal.
2. In the context of steam sterilization, ‘superheated steam’ is most similar in behavior to:
A. Hot air
B. Saturated steam
,C. Wet steam
D. Hydrogen peroxide gas
Answer: A
Conceptual Explanation: Superheated steam is steam that has reached a temperature
higher than its boiling point for a given pressure. It lacks moisture and behaves like hot air,
which is an ineffective sterilant.
3. Which regulatory agency is responsible for the regulation of ethylene oxide (EtO) emissions
into the outdoor environment?
A. EPA
B. FDA
C. OSHA
D. CDC
Answer: A
Conceptual Explanation: While OSHA regulates worker exposure to EtO, the
Environmental Protection Agency (EPA) regulates the impact of EtO emissions on the
environment under the Clean Air Act.
4. A Type 5 integrating indicator is designed to react to which of the following?
A. Temperature only
B. Time and temperature only
, C. The presence of Geobacillus stearothermophilus
D. All critical parameters of the sterilization cycle
Answer: D
Conceptual Explanation: Type 5 integrating indicators are designed to react to all critical
variables (time, temperature, and moisture/pressure) and correlate to the performance of
a biological indicator.
5. Which of the following processes occurs during the ‘cavitation’ phase of an ultrasonic
cleaner?
A. Spray arms rotate to provide impingement
B. High-frequency sound waves create imploding bubbles
C. Water is heated to 140 degrees Fahrenheit to kill bacteria
D. Chemical vapors are injected to dissolve lipids
Answer: B
Conceptual Explanation: Cavitation is the process where high-frequency sound waves
create microscopic bubbles that implode upon contact with instruments, drawing soil away
from the surface.
6. According to AAMI ST79, what is the maximum recommended weight for a wrapped
instrument set?
A. 15 pounds
EXAMINATION QUESTIONS AND
ANSWERS
1. Which of the following is the most effective method for removing biofilm from the internal
channels of a flexible endoscope?
A. Soaking in high-level disinfectant for double the recommended time
B. Automated endoscope reprocessor (AER) cycle without manual pre-cleaning
C. Ultrasonic cleaning at 40 kHz
D. Mechanical brushing with a properly sized brush
Answer: D
Conceptual Explanation: Mechanical action (brushing) is the only reliable way to disrupt
and remove the complex matrix of a biofilm from lumens. Disinfectants cannot penetrate
biofilm effectively without mechanical removal.
2. In the context of steam sterilization, ‘superheated steam’ is most similar in behavior to:
A. Hot air
B. Saturated steam
,C. Wet steam
D. Hydrogen peroxide gas
Answer: A
Conceptual Explanation: Superheated steam is steam that has reached a temperature
higher than its boiling point for a given pressure. It lacks moisture and behaves like hot air,
which is an ineffective sterilant.
3. Which regulatory agency is responsible for the regulation of ethylene oxide (EtO) emissions
into the outdoor environment?
A. EPA
B. FDA
C. OSHA
D. CDC
Answer: A
Conceptual Explanation: While OSHA regulates worker exposure to EtO, the
Environmental Protection Agency (EPA) regulates the impact of EtO emissions on the
environment under the Clean Air Act.
4. A Type 5 integrating indicator is designed to react to which of the following?
A. Temperature only
B. Time and temperature only
, C. The presence of Geobacillus stearothermophilus
D. All critical parameters of the sterilization cycle
Answer: D
Conceptual Explanation: Type 5 integrating indicators are designed to react to all critical
variables (time, temperature, and moisture/pressure) and correlate to the performance of
a biological indicator.
5. Which of the following processes occurs during the ‘cavitation’ phase of an ultrasonic
cleaner?
A. Spray arms rotate to provide impingement
B. High-frequency sound waves create imploding bubbles
C. Water is heated to 140 degrees Fahrenheit to kill bacteria
D. Chemical vapors are injected to dissolve lipids
Answer: B
Conceptual Explanation: Cavitation is the process where high-frequency sound waves
create microscopic bubbles that implode upon contact with instruments, drawing soil away
from the surface.
6. According to AAMI ST79, what is the maximum recommended weight for a wrapped
instrument set?
A. 15 pounds
