Sterile Processing Decontamination Steps: The Complete Order of Operations

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:

1. Soak in enzymatic cleaner at the correct dilution and temperature per manufacturer's IFU
2. Scrub all surfaces with appropriate brushes — use brushes sized for lumens
3. Rinse thoroughly with purified or deionized water
4. 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 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