Why the Order of Decontamination Steps Matters
The decontamination workflow in sterile processing follows a strict one-way, contaminated-to-clean sequence. Getting the order wrong doesn't just cost you points on the CRCST exam — in a real department, it can result in patient infections and regulatory violations. This is one of the most tested topics in the Cleaning, Decontamination & Disinfection domain, which makes up 21% of the CRCST exam.
The Correct Order of Decontamination Steps
Step 1: Point-of-Use Pre-Cleaning (at the OR or procedure room)
The decontamination process begins at the point of use — in the operating room or procedure area — immediately after an instrument is used.
- Wipe gross soil from instruments with a moist sponge or towel
- Keep instruments moist to prevent biofilm formation and drying of organic material
- Never use saline — saline causes corrosion, pitting, and brown/orange staining
- Place instruments in a closed, leak-proof transport container
Key exam point: Pre-cleaning is done by the **surgical team or circulating nurse**, not the sterile processing technician.
Step 2: Safe Transport to the Decontamination Area
Soiled instruments must be transported in a way that protects staff and the environment:
- Use closed, rigid, leak-proof containers or covered transport carts
- Never carry instruments openly in the hallways
- Transport carts should be clearly labeled as biohazardous
- Some facilities use a soiled instrument elevator or dedicated corridor
Step 3: Receiving and Sorting
When instruments arrive in the decontamination area:
- Don full PPE before handling any soiled instruments (gown, gloves, face shield, shoe covers)
- Sort instruments by type and IFU (Instructions for Use) requirements
- Disassemble all multi-part instruments
- Open all hinged instruments (hemostats, scissors, needle holders)
- Remove all disposable components
- Check for sharps and handle with caution
Step 4: Manual Cleaning
Not all instruments can go directly into a mechanical washer. Manual cleaning is required for:
- Delicate instruments that cannot withstand mechanical agitation
- Instruments with complex lumens, channels, or joints
- Items whose IFU specifies manual cleaning only
Manual cleaning process:
- Soak in enzymatic cleaner at the correct dilution and temperature per manufacturer's IFU
- Scrub all surfaces with appropriate brushes — use brushes sized for lumens
- Rinse thoroughly with purified or deionized water
- Never reuse enzymatic cleaning solution — change between each use
Step 5: Mechanical Cleaning
Mechanical cleaning is preferred whenever possible because it is more consistent and reduces staff exposure to bloodborne pathogens.
Ultrasonic Cleaner:
- Uses cavitation to remove soil from crevices and surfaces
- Must be degassed when solution is changed
- Instruments must be fully submerged with hinged items open
- Run time: typically 3–10 minutes
- Change solution at least daily or when visibly soiled
Washer-Disinfector:
- Cleans and thermally disinfects in a single cycle
- Uses detergent, hot water, and heat
- Final rinse temperature typically 80–93°C for thermal disinfection
- Items must be properly loaded — nothing blocking spray arms
Step 6: Inspection
After cleaning, every instrument must be inspected before moving to prep and pack:
- Check for residual soil — especially in box locks, serrations, and lumens
- Test function: ratchets hold, jaws align, scissors cut cleanly
- Look for damage: cracks, pitting, corrosion, bent tips
- Use magnification loupes for fine instruments
- Use a lighted magnifying glass for detailed inspection
Any instrument that fails inspection is pulled from service and sent for repair or replacement.
Step 7: Drying
Instruments must be completely dry before packaging and sterilization:
- Use forced air (air gun) or lint-free towels
- Moisture inside packaging can compromise sterilization and cause wet packs
- Pay special attention to lumens and channels — use air to force water out
Step 8: Transfer to Prep and Pack
The final step in decontamination is transferring clean instruments to the preparation and packaging area:
- Pass instruments through a pass-through window (one-way, never go back)
- The pass-through window separates the contaminated zone from the clean zone
- Never carry instruments back through the decontamination area once they are clean
PPE Requirements for the Decontamination Area
The decontamination area is classified as a contaminated zone and requires full PPE:
| PPE Item | Requirement |
|---|---|
| Gown/apron | Waterproof, fluid-resistant |
| Gloves | Heavy-duty, puncture-resistant |
| Eye protection | Face shield or goggles + mask |
| Footwear | Waterproof shoe covers or dedicated shoes |
PPE must be donned before entering and doffed before leaving the decontamination area. Hand hygiene is performed after doffing.
Common CRCST Exam Questions on Decontamination Steps
Q: What is the FIRST step in the decontamination process?
A: Point-of-use pre-cleaning — performed at the OR immediately after instrument use.
Q: What type of water should NEVER be used for pre-cleaning at point of use?
A: Saline — it causes corrosion and brown/orange staining on stainless steel instruments.
Q: What is the purpose of degassing the ultrasonic cleaner?
A: To remove dissolved air from the solution before use, which maximizes cavitation effectiveness.
Q: What should you use for the final rinse after manual cleaning?
A: Purified, deionized, or distilled water — to prevent mineral deposits and water spots.
Q: What separates the decontamination area from the clean prep and pack area?
A: A pass-through window — instruments move one-way from contaminated to clean.
Official Resources
- CDC Guideline for Disinfection and Sterilization in Healthcare Facilities — The CDC's comprehensive disinfection and sterilization reference
- AAMI ST79 — Comprehensive Guide to Steam Sterilization and Sterility Assurance — ANSI/AAMI standard for instrument preparation and sterilization
- HSPA CRCST Exam Content Outline — Official decontamination domain breakdown