CRCST Certification Review — 9th Edition
(HSPA/Formerly IAHCSMM) | 230 Practice MCQs
with Correct Answers & Rationales
Exam Format: 150 questions | 180 minutes | Pass/Fail | 7 Domains Domain Weights:
Decontamination 23% | Prep & Packaging 19% | Sterilization 19% | Sterile Storage & Inventory
10% | Distribution 9% | Patient Care Equipment 11% | Safety, Infection Control &
Communication 9%
🔹 DOMAIN 1: DECONTAMINATION (Questions 1–53)
1. What is the FIRST step when processing contaminated surgical instruments in the
decontamination area?
A) Sterilize immediately
B) Point-of-use pre-treatment/pre-cleaning at the surgical site (correct answer)
C) Soak in enzymatic detergent for 30 minutes
D) Inspect for damage before cleaning
Rationale: Point-of-use pre-treatment — removing gross soil and keeping instruments moist
before transport — prevents biofilm formation and protects against dried-on organic matter,
making final cleaning more effective.
2. Biofilm is MOST dangerous in sterile processing because:
A) It causes discoloration of instrument surfaces
B) It protects microorganisms from cleaning agents and sterilization (correct answer)
C) It damages instrument coatings permanently
D) It indicates improper storage conditions
Rationale: Biofilm is a structured community of microorganisms encased in a protective matrix.
It significantly increases resistance to detergents and even sterilization, making early cleaning
critical.
3. The decontamination area should maintain which air pressure relationship compared to
adjacent areas?
, A) Positive pressure
B) Neutral pressure
C) Negative pressure (correct answer)
D) Pressure is irrelevant to infection control
Rationale: The decontamination area must be under negative air pressure to prevent
contaminated air from flowing into clean preparation and sterile storage areas.
4. Which personal protective equipment (PPE) is required when working in the
decontamination area?
A) Gloves only
B) Gloves, mask, and eye protection only
C) Gloves, fluid-resistant gown, mask, eye protection, and shoe covers (correct answer)
D) Gloves and a surgical gown
Rationale: Full PPE in decontamination (gloves, fluid-resistant gown/apron, mask/face shield,
eye protection, and shoe/leg covers) protects the technician from blood, body fluids, and
aerosols created during cleaning.
5. The purpose of using an enzymatic detergent during instrument cleaning is to:
A) Sterilize the instrument surface
B) Break down proteins, fats, and carbohydrates in organic soil (correct answer)
C) Disinfect instruments to a high level
D) Remove mineral deposits from metal surfaces
Rationale: Enzymatic cleaners contain specific enzymes (proteases, lipases, amylases) that
chemically digest organic matter — bioburden, blood, and tissue — making mechanical removal
easier.
6. Which type of water is BEST for the final rinse of surgical instruments to prevent
mineral spotting?
A) Hot tap water
B) Cold tap water
C) Deionized or distilled water (correct answer)
D) Filtered water
,Rationale: Deionized or distilled water removes mineral ions that cause spotting, staining, and
residue on instruments. Hard water leaves calcium and magnesium deposits.
7. Ultrasonic cleaners work by which mechanism?
A) High-temperature steam loosening debris
B) Cavitation — the implosion of microscopic bubbles that dislodge soil (correct answer)
C) Chemical dissolution of organic matter
D) High-pressure water jets removing debris
Rationale: Ultrasonic cleaning uses high-frequency sound waves in liquid to create cavitation —
tiny bubbles that implode and release energy, removing soil from instrument surfaces and
crevices.
8. After ultrasonic cleaning, instruments must be:
A) Packaged immediately for sterilization
B) Rinsed thoroughly to remove detergent and loosened soil (correct answer)
C) Air-dried for 30 minutes before further processing
D) Inspected under magnification before rinsing
Rationale: Instruments must be thoroughly rinsed after ultrasonic cleaning to remove detergent
residues and loosened bioburden, which could interfere with sterilization or damage tissue.
9. Which of the following instruments should NOT be processed in an ultrasonic cleaner?
A) Hemostatic clamps
B) Scissors
C) Chrome-plated instruments (correct answer)
D) Needle holders
Rationale: Chrome-plated instruments and instruments with cement-bonded components (some
optics, lenses) should not be ultrasonically cleaned — cavitation can damage the plating or
dissolve cement.
10. Washer-disinfectors provide what level of disinfection?
A) Sterilization
, B) Low-level disinfection
C) Intermediate-level disinfection
D) Thermal disinfection (high-level for heat-stable items) (correct answer)
Rationale: Washer-disinfectors use thermal disinfection (hot water rinse cycle at 80–93°C /
176–199°F), achieving high-level equivalent disinfection for heat-stable instruments.
11. The A0 value in thermal disinfection refers to:
A) The starting temperature of the wash cycle
B) A measure of the lethality of a moist heat disinfection process (correct answer)
C) The concentration of enzymatic detergent used
D) The number of log reductions achieved by a disinfectant
Rationale: A0 is a concept from ISO 15883 that quantifies the effectiveness of thermal
disinfection. An A0 of 600 (80°C for 10 minutes) is recommended for most medical devices.
12. The purpose of instrument lubrication ("milking") in decontamination is to:
A) Make instruments easier to open and close during inspection
B) Protect metal surfaces from corrosion and keep moving parts functional (correct
answer)
C) Add a protective coating before sterilization
D) Help identify instrument defects under lighting
Rationale: Water-soluble instrument lubricant ("instrument milk") protects metal surfaces from
corrosion, keeps box locks and joints functioning smoothly, and is sterilization-compatible.
13. Oil-based lubricants should NOT be used on surgical instruments because:
A) They cause discoloration of instrument surfaces
B) They are not sterilization-compatible and can prevent steam or gas penetration (correct
answer)
C) They make instruments slippery and difficult to handle
D) They are not approved by the FDA
Rationale: Oil-based (petroleum) lubricants are NOT sterilization-compatible. They coat
instrument surfaces and prevent steam or EO gas from contacting all areas, resulting in
sterilization failure.
(HSPA/Formerly IAHCSMM) | 230 Practice MCQs
with Correct Answers & Rationales
Exam Format: 150 questions | 180 minutes | Pass/Fail | 7 Domains Domain Weights:
Decontamination 23% | Prep & Packaging 19% | Sterilization 19% | Sterile Storage & Inventory
10% | Distribution 9% | Patient Care Equipment 11% | Safety, Infection Control &
Communication 9%
🔹 DOMAIN 1: DECONTAMINATION (Questions 1–53)
1. What is the FIRST step when processing contaminated surgical instruments in the
decontamination area?
A) Sterilize immediately
B) Point-of-use pre-treatment/pre-cleaning at the surgical site (correct answer)
C) Soak in enzymatic detergent for 30 minutes
D) Inspect for damage before cleaning
Rationale: Point-of-use pre-treatment — removing gross soil and keeping instruments moist
before transport — prevents biofilm formation and protects against dried-on organic matter,
making final cleaning more effective.
2. Biofilm is MOST dangerous in sterile processing because:
A) It causes discoloration of instrument surfaces
B) It protects microorganisms from cleaning agents and sterilization (correct answer)
C) It damages instrument coatings permanently
D) It indicates improper storage conditions
Rationale: Biofilm is a structured community of microorganisms encased in a protective matrix.
It significantly increases resistance to detergents and even sterilization, making early cleaning
critical.
3. The decontamination area should maintain which air pressure relationship compared to
adjacent areas?
, A) Positive pressure
B) Neutral pressure
C) Negative pressure (correct answer)
D) Pressure is irrelevant to infection control
Rationale: The decontamination area must be under negative air pressure to prevent
contaminated air from flowing into clean preparation and sterile storage areas.
4. Which personal protective equipment (PPE) is required when working in the
decontamination area?
A) Gloves only
B) Gloves, mask, and eye protection only
C) Gloves, fluid-resistant gown, mask, eye protection, and shoe covers (correct answer)
D) Gloves and a surgical gown
Rationale: Full PPE in decontamination (gloves, fluid-resistant gown/apron, mask/face shield,
eye protection, and shoe/leg covers) protects the technician from blood, body fluids, and
aerosols created during cleaning.
5. The purpose of using an enzymatic detergent during instrument cleaning is to:
A) Sterilize the instrument surface
B) Break down proteins, fats, and carbohydrates in organic soil (correct answer)
C) Disinfect instruments to a high level
D) Remove mineral deposits from metal surfaces
Rationale: Enzymatic cleaners contain specific enzymes (proteases, lipases, amylases) that
chemically digest organic matter — bioburden, blood, and tissue — making mechanical removal
easier.
6. Which type of water is BEST for the final rinse of surgical instruments to prevent
mineral spotting?
A) Hot tap water
B) Cold tap water
C) Deionized or distilled water (correct answer)
D) Filtered water
,Rationale: Deionized or distilled water removes mineral ions that cause spotting, staining, and
residue on instruments. Hard water leaves calcium and magnesium deposits.
7. Ultrasonic cleaners work by which mechanism?
A) High-temperature steam loosening debris
B) Cavitation — the implosion of microscopic bubbles that dislodge soil (correct answer)
C) Chemical dissolution of organic matter
D) High-pressure water jets removing debris
Rationale: Ultrasonic cleaning uses high-frequency sound waves in liquid to create cavitation —
tiny bubbles that implode and release energy, removing soil from instrument surfaces and
crevices.
8. After ultrasonic cleaning, instruments must be:
A) Packaged immediately for sterilization
B) Rinsed thoroughly to remove detergent and loosened soil (correct answer)
C) Air-dried for 30 minutes before further processing
D) Inspected under magnification before rinsing
Rationale: Instruments must be thoroughly rinsed after ultrasonic cleaning to remove detergent
residues and loosened bioburden, which could interfere with sterilization or damage tissue.
9. Which of the following instruments should NOT be processed in an ultrasonic cleaner?
A) Hemostatic clamps
B) Scissors
C) Chrome-plated instruments (correct answer)
D) Needle holders
Rationale: Chrome-plated instruments and instruments with cement-bonded components (some
optics, lenses) should not be ultrasonically cleaned — cavitation can damage the plating or
dissolve cement.
10. Washer-disinfectors provide what level of disinfection?
A) Sterilization
, B) Low-level disinfection
C) Intermediate-level disinfection
D) Thermal disinfection (high-level for heat-stable items) (correct answer)
Rationale: Washer-disinfectors use thermal disinfection (hot water rinse cycle at 80–93°C /
176–199°F), achieving high-level equivalent disinfection for heat-stable instruments.
11. The A0 value in thermal disinfection refers to:
A) The starting temperature of the wash cycle
B) A measure of the lethality of a moist heat disinfection process (correct answer)
C) The concentration of enzymatic detergent used
D) The number of log reductions achieved by a disinfectant
Rationale: A0 is a concept from ISO 15883 that quantifies the effectiveness of thermal
disinfection. An A0 of 600 (80°C for 10 minutes) is recommended for most medical devices.
12. The purpose of instrument lubrication ("milking") in decontamination is to:
A) Make instruments easier to open and close during inspection
B) Protect metal surfaces from corrosion and keep moving parts functional (correct
answer)
C) Add a protective coating before sterilization
D) Help identify instrument defects under lighting
Rationale: Water-soluble instrument lubricant ("instrument milk") protects metal surfaces from
corrosion, keeps box locks and joints functioning smoothly, and is sterilization-compatible.
13. Oil-based lubricants should NOT be used on surgical instruments because:
A) They cause discoloration of instrument surfaces
B) They are not sterilization-compatible and can prevent steam or gas penetration (correct
answer)
C) They make instruments slippery and difficult to handle
D) They are not approved by the FDA
Rationale: Oil-based (petroleum) lubricants are NOT sterilization-compatible. They coat
instrument surfaces and prevent steam or EO gas from contacting all areas, resulting in
sterilization failure.
