What Is a Subcutaneous Syringe? Types, Parts and FDA Class

A subcutaneous syringe is a piston syringe used to deliver a medicinal product into the fatty tissue under the skin. “Subcutaneous” names the injection route, not a separate regulated device type: the syringe itself is classified under the same FDA regulation as other piston syringes, 21 CFR 880.5860, Class II. This page maps the device types used for subcutaneous injection to their FDA classification records, so buyers, clinic staff and students can tell the categories apart.

What a subcutaneous syringe is

Under 21 CFR 880.5860, a piston syringe is a device intended for medical purposes; FDA’s product-code definition describes it as a calibrated hollow barrel and a movable plunger, with a connector at one end for fitting a needle. The regulation classifies piston syringes as Class II (performance standards). Searches for “syringe subcutaneous injection” or “syringe for subcutaneous injection” describe the same thing: a piston syringe, pen injector or prefilled device whose labelling supports the subcutaneous route.

Who uses it: clinicians, nurses and pharmacy staff, and patients who self-administer prescribed products such as insulin, where the product labelling allows it.

How it is built

A conventional piston syringe has three working parts: a calibrated barrel, a plunger that moves inside it, and a nozzle or connector that accepts a needle (or has one attached). FDA’s low-dead-space definition (product code QNQ) describes a syringe designed to reduce medication waste, a design variation on the same barrel-and-plunger structure. Pen injectors and on-body injectors are different mechanisms and are listed separately below.

Types used for subcutaneous injection, and their FDA records

The table lists FDA product codes under 21 CFR 880.5860 whose definition or name relates to subcutaneous use or to the same syringe mechanism. Data are from the openFDA device classification database, read 2026-11-07.

Type	FDA product code	Class	What FDA’s record says
Piston syringe	FMF	2	General piston syringe category.
Antistick syringe	MEG	2	Listed as “Syringe, Antistick”.
Epinephrine syringe	PQX	2	“Intended for intramuscular or subcutaneous injection of epinephrine.”
Low dead space piston syringe	QNQ	2	A piston syringe “designed to reduce medication waste”.
Pen injector	NSC	2	A nonelectrically-powered, mechanically-operated device that injects a dose of medicinal product from a cartridge, reservoir or syringe through a hypodermic needle.
On-body injector	QLF	2	A prescription device adhered to the body that injects single or multiple doses from a cartridge or reservoir, per FDA-approved labelling.

Not every code above is limited to the subcutaneous route; the route a given product supports is set by its own labelling. For insulin-specific syringes see insulin syringe sizing, needle gauge and volume, and for tuberculin-style 1 mL formats see tuberculin needles.

Sizes and specifications

Barrel volume, needle gauge and needle length vary by product and are set out in each manufacturer’s instructions for use. For insulin syringes, the sizing relationships are covered on the insulin syringe sizing page. One sourced specification: ISO 7886-1 sets a maximum dead space of 0.07 mL for syringes under 5 mL, according to Krisdiyanto et al., Medicine 101(49):e31812 (PMC9750608).

Safe use and handling basics

• The CDC states: use a new sterile syringe and needle for each patient.
• CDC: a used syringe and needle are both contaminated and must be discarded.
• CDC: never reuse a needle or syringe on more than one patient. Its summary rule is “One Needle, One Syringe, Only One Time.”

Source: CDC injection safety guidance for healthcare providers (cdc.gov/injection-safety), read 2026-11-07. Follow the product’s instructions for use and your facility’s policy; this page gives no dosing or technique instructions.

Common mistakes

• Treating “subcutaneous syringe” as a distinct product class. It is a description of route; check the product’s own labelling for the routes it supports.
• Assuming product codes are interchangeable. FDA lists epinephrine, pen, on-body and standard piston syringes under separate codes, so equivalence must come from the labelling, not the shared regulation.
• Reusing a syringe or needle between patients, which the CDC states must never happen.

FAQ

What is a subcutaneous syringe?

A piston syringe (barrel, plunger, needle connector) used for delivering a product under the skin. FDA regulates piston syringes under 21 CFR 880.5860 as Class II.

Is there a specific syringe for subcutaneous injection?

FDA has no separate “subcutaneous syringe” code. Related codes include epinephrine syringes (intramuscular or subcutaneous), pen injectors and on-body injectors, each defined by its own labelling.

Can a syringe be reused for subcutaneous injection?

No. The CDC states that syringes and needles must never be reused on more than one patient, and a used syringe and needle must be discarded.

Where can I see what an injection kit contains?

See the injection kit page, and the bulk insulin syringes page for insulin-syringe packaging.

Sources

• 21 CFR 880.5860, Piston syringe (law.cornell.edu/cfr/text/21/880.5860), read 2026-11-07.
• openFDA device classification API, regulation number 880.5860 (api.fda.gov/device/classification.json), read 2026-11-07.
• CDC, Injection safety for healthcare providers (cdc.gov/injection-safety/hcp/clinical-safety/index.html), read 2026-11-07.
• Krisdiyanto et al., Medicine 101(49):e31812, PMC9750608.