Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
Who uses this: sterile processing staff, clinic and surgical-center teams, infection preventionists and buyers who need to understand how reusable surgical instruments move from used to ready for the next patient.
Short answer: clean first, then sterilize
Reusable surgical instruments are cleaned, dried and inspected before they are wrapped and sterilized. The CDC states that residues left on instruments reduce the effectiveness of high-level disinfection and sterilization, so a sterilizer cycle cannot make up for poor cleaning. Where the maker of an instrument gives its own reprocessing instructions, those instructions come first; see ISO 17664 reprocessing information.
The sequence covered below follows the CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (a 2008 guideline; the CDC pages carry a date of November 28, 2023): keep soil from drying, clean, rinse and dry, inspect, package, sterilize, monitor, and store.
Cleaning surgical instruments: methods compared
The CDC describes several cleaning routes. They are often combined, not alternatives.
| Method | What the CDC says it is for | Caveat stated by the CDC |
|---|---|---|
| Manual cleaning | Relies on friction and fluidics; used where no mechanical unit is available, or for fragile or hard-to-clean instruments | Follow the instrument maker’s instructions for fragile items |
| Ultrasonic cleaning | Cavitation disrupts the bonds that hold particles to the surface | Used solutions can harbor bacteria, and the cleaning fluid could result in endotoxin contamination of surgical instruments |
| Automated washer-disinfector | Computer-controlled units that clean, disinfect and dry | Avoid stacking instruments in the washer; open hinged instruments fully |
| Enzymatic cleaner | Neutral or near-neutral pH detergents with enzymes are preferred for delicate instruments | Enzymatic cleaners are not disinfectants; follow the maker’s dilution and contact time; enzymes must be rinsed away |
Alkaline cleaners dissolve protein and fat, according to the CDC, but can be corrosive. More on the equipment: washer-disinfectors.
Before cleaning: keep soil from drying
The CDC states that surgical instruments should be presoaked or rinsed to prevent drying of blood. Dried-on soil is harder to remove and, as noted above, residues compromise later disinfection and sterilization.
Rinsing, drying and inspection
The CDC requires that items be cleaned, dried and inspected before they are wrapped or placed in rigid containers. At a minimum, all instruments should be individually inspected and be visibly clean. The CDC also notes that no real-time test verifies cleaning in clinical settings; verification testing such as microbiologic sampling exists but is not routinely recommended. Visual inspection is therefore the working check, and an instrument that is not visibly clean is not ready for wrapping.
Packaging and loading
- Open hinged instruments, and disassemble items with removable parts unless the manufacturer says otherwise.
- Position concave surfaces so they drain, and keep heavy items from damaging delicate ones.
- The packaging material must allow penetration of the sterilant; avoid tenting and gapping.
- Arrange the load so all surfaces are directly exposed to the sterilizing agent. Basins go on edge, small items go loosely in wire baskets, and peel packs go on edge in perforated or mesh racks.
Sterilizing surgical instruments with steam
Steam is recommended for critical and semicritical items that are heat and moisture resistant. The CDC names four parameters: steam, pressure, temperature and time. Ideal steam is dry saturated steam with a dryness fraction of at least 97%.
| Cycle type | Temperature | Minimum exposure (wrapped healthcare supplies) |
|---|---|---|
| Gravity displacement | 121 C (250 F) | 30 minutes |
| Prevacuum | 132 C (270 F) | 4 minutes |
| Flush-pressure pulsing (porous loads and instruments) | 132-135 C | 3-4 minutes |
In gravity displacement, incomplete air removal slows steam penetration of porous items. In prevacuum cycles a vacuum pump removes air first, giving nearly instantaneous steam penetration even into porous loads. These are general CDC minimums; the instrument maker’s instructions and the sterilizer maker’s validated cycles take precedence. See autoclave cycle types.
Monitoring the cycle
- Mechanical: the cycle printout and gauges.
- Chemical: indicators placed outside and inside packs.
- Biological: spore tests using Geobacillus stearothermophilus.
- Bowie-Dick: a test of air removal used each day a vacuum-type steam sterilizer is in use, before the first processed load, run at 134 C for 3.5 minutes. The CDC describes acceptable performance as a uniform color change on the test sheet, and says a sterilizer that fails should not be used until the maintenance personnel have inspected it.
Storage and event-related shelf life
The CDC states that a sterile item stays sterile until some event causes contamination, such as tears, moisture or handling. Reported examples are heat-sealed pouches and polyethylene-overwrapped packs sterile up to 9 months, and double-thickness muslin at least 30 days. Store items away from sinks and wet locations, 8-10 inches from the floor, 2 inches from outside walls and at least 18 inches from sprinkler heads. Handle sterilized items with aseptic technique. See event-related sterility and sterile storage.
Common mistakes
- Letting blood dry on instruments instead of presoaking or rinsing them.
- Stacking instruments in a washer or leaving hinged instruments closed.
- Treating an enzymatic cleaner as a disinfectant, or not rinsing the enzymes away.
- Reusing ultrasonic solution that has become contaminated.
- Wrapping instruments that have not been dried and inspected.
- Applying generic times to complex instruments instead of the manufacturer’s instructions and test data.
FAQ
What is the difference between cleaning and sterilizing surgical instruments?
Cleaning removes visible soil and residues; sterilization is the later step that uses a validated process such as steam. The CDC states that residues reduce sterilization effectiveness, so cleaning comes first.
Can enzymatic cleaner sterilize instruments?
No. The CDC states that enzymatic cleaners are not disinfectants.
How is steam sterilization of surgical instruments done?
Wrapped or contained instruments are exposed to dry saturated steam; the CDC gives common minimums of 30 minutes at 121 C (gravity displacement) and 4 minutes at 132 C (prevacuum), subject to the maker’s instructions.
How do you know instruments are clean before sterilization?
Each instrument is individually inspected and must be visibly clean; the CDC notes there is no real-time test of cleaning in clinical settings.
Which standard covers this?
Steam sterilization practice in healthcare facilities is covered by ANSI/AAMI ST79. The manufacturer’s information is described in ISO 17664. For the wider reprocessing picture see medical device reprocessing.
Sources
- CDC, Cleaning (Guideline for Disinfection and Sterilization in Healthcare Facilities), checked 2026-10-30.
- CDC, Steam Sterilization, checked 2026-10-30.
- CDC, Sterilizing Practices, checked 2026-10-30.
