Cssd technicians exam
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Here are 20 hard-level CSSD technician MCQs covering all major topic areas. Answers and explanations are at the end.
CSSD Technician Exam - Practice MCQs (Hard Level)
SECTION 1: Sterilization Methods
1. The D-value in sterilization refers to:
- A) The depth of penetration of steam into a pack
- B) The time required to reduce a microbial population by 90% (1 log cycle) at a given temperature
- C) The drying time post-autoclave cycle
- D) The decimal reading of a chemical indicator strip
2. Which sterilization method is most appropriate for heat-sensitive, moisture-sensitive items such as fiber-optic cables?
- A) Steam autoclave at 134°C
- B) Hydrogen peroxide gas plasma (e.g., STERRAD)
- C) Dry heat oven at 160°C
- D) Ethylene oxide (EtO) - immediate use after cycle
3. The standard pre-vacuum (high pre-vacuum) steam sterilization cycle for wrapped instruments runs at:
- A) 121°C for 15 minutes
- B) 134°C for 3-4 minutes
- C) 132°C for 10 minutes
- D) 160°C for 2 hours
4. Which of the following is the CORRECT order of the Spaulding Classification from highest to lowest infection risk?
- A) Non-critical → Semi-critical → Critical
- B) Semi-critical → Critical → Non-critical
- C) Critical → Semi-critical → Non-critical
- D) Critical → Non-critical → Semi-critical
5. A biological indicator (BI) used to monitor steam sterilization contains spores of:
- A) Bacillus atrophaeus
- B) Geobacillus stearothermophilus
- C) Clostridium difficile
- D) Mycobacterium tuberculosis
SECTION 2: Decontamination & Cleaning
6. When processing a contaminated surgical instrument, the correct order of the decontamination process is:
- A) Sterilize → Inspect → Clean → Decontaminate
- B) Decontaminate → Inspect → Package → Sterilize
- C) Rinse → Inspect → Dry → Sterilize
- D) Pre-clean → Clean → Rinse → Inspect → Package → Sterilize
7. The primary purpose of an ultrasonic cleaner in CSSD is to:
- A) Sterilize instruments using ultrasonic energy
- B) Remove soil from lumens and crevices through cavitation
- C) Disinfect instruments to a high level using sound waves
- D) Dry instruments before packaging
8. Which water quality is recommended for the FINAL rinse in automated washer-disinfectors?
- A) Tap water
- B) Softened water
- C) Purified/deionized water (conductivity ≤15 µS/cm)
- D) Distilled water mixed with detergent
9. A washer-disinfector thermal disinfection cycle must achieve an A0 value of at least:
- A) 60
- B) 300
- C) 600
- D) 3000
10. When cleaning a flexible endoscope after use, which step should be performed FIRST - even before returning to CSSD?
- A) Leak testing
- B) High-level disinfection (HLD) in glutaraldehyde
- C) Bedside pre-cleaning (wiping and flushing channels)
- D) Visual inspection under magnification
SECTION 3: Packaging & Storage
11. The standard color indicator for Class 1 chemical indicators (process indicators) is:
- A) Turns from blue to pink - confirms sterilization achieved
- B) Changes color to indicate the item was exposed to the sterilization process (not sterility assurance)
- C) Remains unchanged unless the temperature drops below 100°C
- D) Turns black only if moisture is present in the pack
12. Which of the following packaging materials is NOT suitable for steam sterilization?
- A) Crepe paper wrap
- B) Non-woven polypropylene fabric (SMS wrap)
- C) Polyethylene/nylon pouches (standard peel pouches)
- D) Nylon film alone (without a paper side)
13. The maximum recommended shelf life for a sterilized item wrapped in standard linen (cloth wrap) stored in open shelving is:
- A) Indefinite, as long as the package is intact
- B) 7 days
- C) 30 days
- D) 6 months
14. According to AAMI/ISO standards, the minimum seal width for heat-sealed peel pouches is:
- A) 3 mm
- B) 6 mm
- C) 10 mm
- D) 15 mm
SECTION 4: Quality Assurance & Testing
15. The Bowie-Dick test is performed:
- A) Daily, at the beginning of the day in an empty pre-vacuum sterilizer, before processing any load
- B) Weekly, in the middle of a mixed instrument load
- C) On every load that contains hollow instruments
- D) Monthly as part of the annual sterilizer validation
16. What does a FAILED Bowie-Dick test indicate?
- A) The steam is not hot enough (temperature failure)
- B) Air removal from the chamber was inadequate (residual air pocket)
- C) The biological indicator was not inactivated
- D) The chemical indicator reached its color endpoint too early
17. Which class of chemical indicator (per ISO 11140-1) provides the MOST information about the sterilization process conditions?
- A) Class 1 (process indicators)
- B) Class 2 (Bowie-Dick test indicators)
- C) Class 4 (multi-variable indicators)
- D) Class 6 (emulating indicators - cycle verification indicators)
18. An ethylene oxide (EtO) sterilizer biological indicator uses spores of:
- A) Geobacillus stearothermophilus
- B) Bacillus atrophaeus (formerly B. subtilis var. niger)
- C) Bacillus cereus
- D) Clostridium sporogenes
SECTION 5: Infection Control, Safety & Regulations
19. When handling contaminated sharps and instruments in the decontamination area, CSSD staff MUST wear:
- A) Surgical mask and apron only
- B) Gloves, gown, eye protection, and mask as a minimum (full PPE for decontamination zone)
- C) Sterile gloves to prevent contaminating instruments
- D) Heat-resistant gloves only during unloading of autoclave
20. The term "event-related sterility" means:
- A) Sterility is guaranteed for a fixed time period after the sterilization date
- B) Sterility is maintained as long as the package integrity is uncompromised - not determined by time alone
- C) Items become non-sterile after any contact event with non-sterile surfaces
- D) Expiry dates are only applied to implantable devices
Answers & Explanations
| Q | Answer | Explanation |
|---|---|---|
| 1 | B | The D-value (decimal reduction time) is the time to kill 90% of organisms - foundational concept in sterilization science. |
| 2 | B | H2O2 gas plasma (STERRAD) works at ~50°C and is moisture-free - ideal for heat/moisture-sensitive items. EtO also works but requires long aeration; fiber-optics can be damaged by heat. |
| 3 | B | Pre-vacuum cycles run at 134°C for 3-4 minutes (wrapped). The 121°C/15 min is the gravity displacement (downward displacement) cycle. |
| 4 | C | Spaulding: Critical (enter sterile tissue - must be sterile) → Semi-critical (contact mucous membranes - HLD minimum) → Non-critical (contact intact skin - low-level disinfection). |
| 5 | B | G. stearothermophilus (now Geobacillus stearothermophilus) is used for steam/H2O2 BIs due to high heat resistance. B. atrophaeus is used for EtO/dry heat. |
| 6 | D | The correct workflow: pre-clean (point of use) → clean → rinse → inspect → package → sterilize → store. |
| 7 | B | Ultrasonic cleaners use high-frequency sound waves to create cavitation bubbles that implode and remove soil from complex surfaces - they do NOT sterilize. |
| 8 | C | Purified/deionized water prevents mineral deposits (water spots) on instruments and protects sensitive items. Tap water causes staining and corrosion. |
| 9 | B | A0 ≥ 600 is required for instruments in contact with intact skin; A0 ≥ 3000 for semi-critical items. For general surgical instruments, A0 ≥ 600 is the minimum per ISO 15883. (Note: A0 600 is the commonly tested standard for washer-disinfectors for surgical instruments.) |
| 10 | C | Bedside pre-cleaning (wipe exterior, flush channels with water/enzyme) must happen immediately after use to prevent soil drying - before transport and before any other step. |
| 11 | B | Class 1 indicators (e.g., autoclave tape) show only that an item was exposed to the process - they do NOT confirm sterilization conditions were met. |
| 12 | D | Plain nylon film (plastic side only) does not allow steam penetration. Peel pouches need one paper/Tyvek side for steam to enter. |
| 13 | B | Linen (woven cloth) wrap on open shelving has a shelf life of ~7 days due to poor barrier properties. Event-related sterility is used for rigid containers and better barrier wraps. |
| 14 | B | AAMI ST79 and ISO 11607 specify a minimum 6 mm seal width for heat-sealed pouches. |
| 15 | A | The Bowie-Dick test is run daily, first thing in the morning, in an empty pre-vacuum sterilizer as a standard check before patient loads. |
| 16 | B | A failed Bowie-Dick = inadequate air removal. Residual air prevents steam from reaching the center of the test pack - indicating a sterilizer fault (not a temperature failure per se). |
| 17 | D | Class 6 (emulating/cycle verification indicators) respond to all critical parameters (temperature, time, steam) and are the most informative. Class 5 (integrating indicators) are also high level. |
| 18 | B | Bacillus atrophaeus is the BI organism for EtO (and dry heat) sterilization. G. stearothermophilus is for steam. |
| 19 | B | Full PPE (heavy-duty gloves, fluid-resistant gown, eye protection, surgical mask) is mandatory in the decontamination (dirty) zone. Sterile gloves are not used - they are for sterile fields only. |
| 20 | B | Event-related sterility means an item stays sterile indefinitely as long as the packaging barrier remains intact - sterility is compromised by events (tears, moisture, contamination), not by time alone. |
Score Guide:
- 18-20 correct: Excellent - exam-ready
- 14-17 correct: Good - review weak areas
- 10-13 correct: Fair - targeted study needed
- Below 10: Foundational review recommended
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