Suture Size Chart — USP to Metric Conversion & Selection Guide
How does suture sizing work?
The USP suture sizing system uses a combination of numbers and zeroes. Starting from 0, sizes increase as: 0, 1, 2, 3, 4, 5, 6, 7 (larger diameter). Below zero, sizes use the "aught" system: 2/0 (or 2-0), 3/0, 4/0, 5/0, 6/0, and so on down to 12/0 (smallest available). The European Pharmacopoeia uses metric sizes measured in tenths of a millimeter. A USP 2/0 suture corresponds to approximately metric 3.0 (0.3mm diameter).
Choosing the right suture size
The general principle is to use the smallest suture that will adequately hold the tissue together. Larger sutures create more tissue reaction and potentially more scarring. Fine sutures (5/0 to 8/0) are used for delicate tissues — ophthalmic, microsurgery, plastic surgery. Medium sutures (2/0 to 4/0) are the workhorses of general surgery — skin closure, subcutaneous tissue, organ repair. Heavy sutures (0 to #2) are used for fascia, tendon, and orthopedic applications requiring maximum strength.
Suture size by surgical specialty
Ophthalmic surgery typically uses 8/0 to 10/0. Plastic and cosmetic surgery uses 5/0 to 6/0 for skin. General surgery uses 2/0 to 3/0 for most closures. Orthopedic surgery uses 0 to #2 for tendon and fascia repair. Cardiovascular surgery uses 4/0 to 7/0 depending on vessel size. Pediatric surgery generally uses one size finer than the equivalent adult procedure.
Side-by-Side Comparison
| Feature | Smaller Sutures (Fine) | Larger Sutures (Heavy) |
|---|---|---|
| USP 8/0 | Metric 0.4 (0.04mm) | Ophthalmic, microsurgery |
| USP 7/0 | Metric 0.5 (0.05mm) | Ophthalmic, vascular |
| USP 6/0 | Metric 0.7 (0.07mm) | Plastic surgery, pediatric |
| USP 5/0 | Metric 1.0 (0.10mm) | Face, hand, cosmetic |
| USP 4/0 | Metric 1.5 (0.15mm) | Skin, subcutaneous, vascular |
| USP 3/0 | Metric 2.0 (0.20mm) | Skin, muscle, peritoneum |
| USP 2/0 | Metric 3.0 (0.30mm) | General closure, fascia |
| USP 0 | Metric 3.5 (0.35mm) | Fascia, tendon, orthopedic |
| USP 1 | Metric 4.0 (0.40mm) | Fascia, heavy tissue |
| USP 2 | Metric 5.0 (0.50mm) | Orthopedic, sternal closure |
Recommended Desmo Care Products
Frequently Asked Questions
What does 3/0 suture mean?
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3/0 (also written as 3-0 or 000) suture means "three aught" — it has a diameter of approximately 0.20mm (metric 2.0). The more zeroes, the finer the suture. 3/0 is a medium-sized suture commonly used for skin closure and general soft tissue approximation in adult patients.
What is the most commonly used suture size?
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The most commonly used suture sizes are 2/0, 3/0, and 4/0. These medium-sized sutures cover the majority of general surgical applications including skin closure, subcutaneous tissue approximation, and organ repair. The exact choice depends on tissue type, location, and patient factors.
What size suture is used for skin closure?
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For skin closure: face and cosmetic areas typically use 5/0 to 6/0. Trunk and extremities use 3/0 to 4/0. Scalp and areas under tension use 2/0 to 3/0. The general rule is to use the smallest suture that adequately holds the tissue to minimize scarring.
What is the difference between USP and metric suture sizes?
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USP sizes use the American numbering system (aught system below zero, integers above). Metric sizes measure the suture diameter in tenths of a millimeter. For example, USP 3/0 = Metric 2.0 (0.20mm diameter). The European Pharmacopoeia uses metric sizing while the US primarily uses USP.
What suture sizes does Desmo Care offer?
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Desmo Care sutures are available from USP 8/0 (finest) to USP #2 (heaviest) across our product portfolio. Our absorbable sutures (DesmoNex, DesmoCryl, DesmoPol, DesmoCapro) and non-absorbable sutures (DesmoMid, DesmoSilk, DesmoLen, DesmoSter) cover all common surgical size requirements.
Need help choosing the right suture?
Our interactive Suture Selector tool recommends the best Desmo Care product based on your surgical specialty, tissue type, and clinical requirements.