Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
A sterilization wrap is a sheet of packaging material that encloses a medical device or instrument set so it can be sterilized and then stay sterile until it is opened for use. Under 21 CFR 880.6850, FDA classifies it as a Class II device, and each wrap is cleared for specific sterilization methods rather than for every sterilizer.
Who uses it: sterile processing and central supply staff, surgical and dental clinics, and the buyers and students who work with them.
What a sterilization wrap is
FDA’s regulation (21 CFR 880.6850) defines a sterilization wrap as a device “intended to be used to enclose another medical device that is to be sterilized by a health care provider. It is intended to allow sterilization of the enclosed medical device and also to maintain sterility of the enclosed device until used.” The regulation lists the wrap, pack, sterilization wrapper, bag and accessories under this one device type, and classifies it as Class II.
The wrap has two jobs that pull against each other: it must let the sterilant reach the contents, and it must then keep microorganisms out. The CDC’s sterilizing practices page states both requirements, that packaging must “allow penetration of the sterilant” and “provide an effective barrier to microbial penetration.”
What sterilization wrap is made of (SMS and woven fabric)
The CDC names two families: woven and nonwoven sterilization wraps. The woven example it describes is double-thickness muslin. The nonwoven family is where “SMS” belongs.
SMS stands for spunbond-meltblown-spunbond, a three-layer (trilaminate) nonwoven. In FDA 510(k) K181174 (FDA letter dated December 11, 2018), one manufacturer’s wrap is described as 100% polypropylene SMS nonwoven, supplied as a single-layer sheet or as a two-sheet version that is ultrasonically bonded, in six models (CH100 to CH600), and labeled single-use. That is one cleared product, not a definition of every SMS wrap.
Wrap, pouch or rigid container
The CDC lists the ways a facility can maintain sterility after processing: rigid containers, peel-open pouches, roll stock, and sterilization wraps (woven and nonwoven). It notes that facilities may use all of them. The table below restates the CDC’s list; for pouches see sterilization pouches.
| Packaging option (CDC) | Source statement |
|---|---|
| Sterilization wraps, woven and nonwoven | Listed by the CDC as an option to maintain sterility; wraps are applied to avoid “tenting and gapping” and multiple layers are used because of the “rigors of handling.” |
| Rigid containers | Listed by the CDC as an option. |
| Peel-open pouches | Listed by the CDC as an option. |
| Roll stock | Listed by the CDC as an option. |
What a 510(k) says a wrap is validated for
The most useful thing to understand about a wrap is that FDA clears it per sterilization method. The table shows the indications in K181174, one manufacturer’s wrap, as an example of how specific the claims are. Another wrap will have different parameters in its own instructions for use and clearance.
| Method (K181174) | Validated parameters in the clearance |
|---|---|
| Gravity-displacement steam | 250°F (121°C) for 30 minutes |
| Pre-vacuum steam | 270°F (132°C) for 4 minutes |
| 100% ethylene oxide | 725 to 735 mg/l at 131°F (55°C), 40 to 80% relative humidity, 60 minutes; aeration 8 hours at 55°C |
| Hydrogen peroxide gas plasma and vaporized hydrogen peroxide | STERRAD 100S, NX, 100NX and 200; STERIS V-PRO; STERIZONE VP4 |
The same clearance validates a dry time of 20 minutes for models CH100 and CH200 and 30 minutes for CH300 to CH600. Lumen claims are also stated per model, for example 3 mm by 400 mm for CH400 to CH600 in steam. For how the methods differ, see sterilization technology, gravity vs vacuum autoclaves and low-temperature sterilization method selection.
Wrapping and storage basics (CDC)
- Packaging that is not acceptable for ethylene oxide or hydrogen peroxide gas plasma “should not be used to wrap medical items” for those methods.
- Wrap is applied so as to avoid tenting and gapping.
- The CDC describes an event-related approach: a packaged item “should remain sterile until some event causes the item to become contaminated.” See event-related sterility and sterile storage.
- For storage, the CDC states that supplies wrapped in double-thickness muslin comprising four layers, or equivalent, remain sterile for at least 30 days, and advises storing items 8 to 10 inches off the floor, not under sinks or where wet, with closed cabinets ideal.
The sterilizer itself is covered in what is an autoclave.
Common mistakes
- Assuming any wrap works in any sterilizer. A clearance lists specific methods, as the table above shows.
- Using a wrap material not suited to ethylene oxide or gas plasma for those cycles (CDC).
- Wrapping loosely enough to leave gaps or tents (CDC).
- Following one manufacturer’s cycle parameters for a different manufacturer’s wrap. Use the instructions for use for the wrap in your hands.
FAQ
What is SMS sterilization wrap?
SMS is a three-layer nonwoven made of spunbond, meltblown and spunbond layers. In FDA 510(k) K181174, one manufacturer’s SMS wrap is 100% polypropylene and cleared under 21 CFR 880.6850.
Is sterilization wrap single-use?
The K181174 wrap is labeled single-use. Woven muslin is described separately by the CDC. Check the instructions for use of the specific wrap.
Can any sterilization wrap go in any sterilizer?
No. FDA clearances list the sterilization methods and parameters each wrap is validated for, and the CDC says packaging unacceptable for ethylene oxide or gas plasma should not be used for those methods.
What is sterilization wrap material?
The CDC names woven (for example double-thickness muslin) and nonwoven wraps. SMS polypropylene is a nonwoven example.
Sources
- FDA, 21 CFR 880.6850 Sterilization wrap, eCFR, checked 2026-10-30.
- CDC, Sterilizing Practices, cdc.gov, checked 2026-10-30.
- FDA 510(k) K181174, Cardinal Health sterilization wrap, FDA clearance letter dated December 11, 2018, checked 2026-10-30.
