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A 20 mL syringe is a piston syringe whose barrel holds up to 20 milliliters. This page describes products and general use; it is not medical advice. It is written for clinic staff, buyers and students who need to know what the size class is, how its tip styles differ in catalog listings, and which single-use rules apply.
What a 20 mL syringe is
In U.S. device regulation a syringe of this kind is a “piston syringe”: under 21 CFR 880.5860 it “consists of a calibrated hollow barrel and a movable plunger,” its nozzle attaches to a single-lumen hypodermic needle, and it is used to add or remove fluid. The regulation classifies it as Class II (performance standards). The “20 mL” in the name is the nominal capacity of the barrel, not a different device category. Typical users are clinicians, nurses and laboratory staff who handle larger fluid volumes than a 1 mL to 10 mL syringe allows. For the next size down, see what a 10 mL syringe is; for the general device, see what a syringe is.
How it is built
The two parts named in the regulation are the calibrated barrel (the graduated cylinder that holds the fluid) and the plunger (the movable part that draws fluid in or pushes it out). The front of the barrel ends in a nozzle, which is the tip that connects to a needle or other fitting.
Tip styles and what a catalog listing tells you
Manufacturer listings for this size usually name the tip. As one worked example, BD lists SKU 302830 as a “20 mL BD Luer-Lok Syringe only”: Luer-Lok tip, sterile, single-use, GTIN 00382903028306, sold as 48 per shelfpack and 192 per case (BD product page, read 2026-11-08). “Syringe only” means no needle is included. The listing does not state graduation details or materials, so those must come from the product label or instructions for use. Luer-Lok and slip-tip versions are separate catalog items; the differences between tip designs are covered in syringe tip types.
| Listing term | What it tells you | Source |
|---|---|---|
| Syringe only | The listing is for the syringe without a needle | BD product page 302830 |
| Luer-Lok tip | Tip style named by the manufacturer for this SKU | BD product page 302830 |
| Sterile, single-use | Supplied sterile and intended for one use | BD product page 302830 |
| Piston syringe, Class II | FDA device type and class for this kind of syringe | 21 CFR 880.5860 |
Specifications that matter: dead space by size band
Dead space is the fluid left in the syringe tip and needle hub after the plunger is fully pressed. ISO 7886-1 sets a maximum by barrel volume, as reported in Krisdiyanto et al., Medicine 101(49):e31812 (PMC9750608). A 20 mL syringe falls in the 20 to under 30 mL band.
| Nominal barrel volume | ISO 7886-1 maximum dead space |
|---|---|
| 10 to under 20 mL | 0.10 mL |
| 20 to under 30 mL | 0.15 mL |
| 30 to under 50 mL | 0.17 mL |
For syringes designed to minimise this volume, see low dead space syringes.
Safe use and handling basics
The CDC’s injection safety guidance (page dated March 26, 2024, read 2026-11-08) states “One Needle, One Syringe, Only One Time.” It says to use a new sterile syringe and needle for each patient and not to administer medications from the same syringe to more than one patient. Its narrow exception covers repeat doses to a single patient during one procedure under strict aseptic technique, after which the syringe is discarded. These rules apply to a 20 mL syringe exactly as to any other size. Expiry dates are discussed in do syringes expire.
Common mistakes
- Treating a large syringe as reusable between patients because it holds more volume; the CDC rule is per patient and per use.
- Assuming a listing states details it does not, such as graduation or materials; take these from the label or instructions for use.
- Confusing “syringe only” with a syringe-and-needle set.
FAQ
How do I read an insulin syringe?
Insulin syringes are a different, much smaller size class from a 20 mL syringe, and their scale is marked in units rather than milliliters. Follow the product’s own label or instructions for use, and see insulin syringe sizing, needle gauge and volume. This page gives no dosing guidance.
How do I read a 1 mL syringe?
A 1 mL syringe is also a different size class. Reading its scale depends on the graduation printed on that product, so use the manufacturer’s instructions for use for the specific syringe, and ask a clinician about any prescribed amount.
Is a 20 mL syringe the same as a 10 mL or 30 mL syringe?
All are piston syringes under the same FDA regulation (21 CFR 880.5860); they differ in nominal barrel volume and, per ISO 7886-1, in maximum dead space.
Sources
- BD, 20 mL BD Luer-Lok Syringe only, product 302830, bd.com, read 2026-11-08.
- 21 CFR 880.5860, Piston syringe, ecfr.gov, read 2026-11-08.
- CDC, Injection Safety: clinical safety, cdc.gov/injection-safety, page dated 2024-03-26, read 2026-11-08.
- Krisdiyanto et al., Medicine 101(49):e31812, PMC9750608 (ISO 7886-1 dead space values).
