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A stainless steel suture is a nonabsorbable surgical suture made of 316L stainless steel. In the United States it is a regulated medical device: the FDA defines it in 21 CFR 878.4495 as a needled or unneedled suture in USP sizes 12-0 through 10, and places it in Class II. It is also called surgical wire, steel suture or wire suture.
This page describes products and general use; it is not medical advice.
Who this is for: clinic staff, buyers and students who need to identify what the term means, how the FDA describes it, and how it differs from the ASTM implant-wire standard that often appears in the same searches. Who uses it: the regulation names abdominal wound closure, intestinal anastomosis, hernia repair and sternal closure as its intended uses.
What it is
Under 21 CFR 878.4495(a), a stainless steel suture is “a needled or unneedled nonabsorbable surgical suture composed of 316L stainless steel, in USP sizes 12-0 through 10, or a substantially equivalent stainless steel suture.” Nonabsorbable means the material is not designed to be broken down by the body; for that general distinction see absorbable vs non-absorbable sutures and the overview What Is a Suture?
How it is built: material and form
The regulation fixes the alloy: 316L stainless steel. The same definition covers sutures supplied with a needle attached (needled) and without one (unneedled), and the classification text refers to a “steel monofilament suture”, and its exemption provision names the steel monofilament suture. For needle vocabulary see suture needle types.
Surgical wire, steel suture and wire suture: the same family of names
“Surgical wire”, “steel suture” and “wire suture” are search and trade terms for this product class. The FDA’s regulation title is “Stainless steel suture”. Sutures made of other materials are separate topics, for example PTFE suture and braided FiberWire, and orthopedic sutures are covered as a wider group.
Types and variants
| Variant | What the regulation says | Key difference |
|---|---|---|
| Needled stainless steel suture | Included in the 878.4495(a) definition | Needle attached to the suture |
| Unneedled stainless steel suture | Included in the 878.4495(a) definition | Supplied without an attached needle |
| Steel monofilament suture, uncoated, no barbs | Exempt from premarket notification (510(k)) under subpart E of part 807, subject to the limitations in 878.9 | The stated exemption applies to this description |
| “Substantially equivalent” stainless steel suture | Also falls within the 878.4495(a) definition | An alternative to the 316L clause in the same definition |
The regulation (b) classifies the device as Class II (special controls). The named special control is FDA’s “Class II Special Controls Guidance Document: Surgical Sutures; Guidance for Industry and FDA.”
Sizes and specifications that matter
The regulation states one size range: USP sizes 12-0 through 10. Manufacturer instructions for use give the diameters and strengths of a specific product.
Intended uses named by the FDA
- Abdominal wound closure
- Intestinal anastomosis
- Hernia repair
- Sternal closure
These are the uses in the regulatory identification. Which suture a clinician selects for a patient is a clinical decision and is outside this page.
Suture standard versus implant wire standard
Searches for surgical wire often surface ASTM F138, “Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants (UNS S31673)”. Its scope covers the chemical, mechanical and metallurgical requirements for that stainless steel bar and wire used to manufacture surgical implants. It is a material specification for implant bar and wire, not the FDA definition of a suture. The FDA regulation 21 CFR 878.4495 is what defines the suture as a device and sets its class.
Reading a product label
A product label or instructions for use should name the material (stainless steel), the USP size and whether a needle is attached. The diameters and strengths of a specific product are given by its manufacturer.
Safe use and handling basics
Use and handling of a specific product follow its manufacturer’s instructions for use. This page does not describe how a suture is placed, twisted or removed.
Common mistakes
- Citing 21 CFR 878.5030 for steel suture. That section covers natural nonabsorbable silk surgical suture; stainless steel suture is 878.4495.
- Treating ASTM F138 as a suture standard. It is an implant bar and wire material specification.
FAQ
What is a stainless steel suture?
It is a needled or unneedled nonabsorbable surgical suture of 316L stainless steel, in USP sizes 12-0 through 10, as defined in 21 CFR 878.4495(a).
Is surgical wire the same as a steel suture?
The terms surgical wire, steel suture and wire suture are used for this product class. The FDA regulation is titled “Stainless steel suture”.
How does the FDA classify it?
Class II (special controls). An uncoated steel monofilament suture without barbs is exempt from premarket notification, subject to the limitations in 21 CFR 878.9.
What is it used for?
The FDA identification lists abdominal wound closure, intestinal anastomosis, hernia repair and sternal closure.
Sources
- U.S. eCFR, 21 CFR 878.4495 Stainless steel suture, checked 2026-11-01 (65 FR 19836, Apr. 13, 2000, as amended 68 FR 32984 and 84 FR 71814).
- ASTM International, ASTM F138-19, Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants (UNS S31673), scope checked 2026-11-01.
