Hypodermic Needles
Hypodermic needles attached to a syringe are used to pierce the skin to inject saline, medications, vaccines, or other medical treatment solutions. They are used when the substance cannot be delivered by mouth or needs to be delivered to muscle or fatty tissue. These needles can also be used to withdraw blood or other body fluids for clinical diagnosis or therapy.
Hypodermic needles are also used in laboratory and research settings to help maintain sterile conditions. For example, they can help reduce contamination of the source material when a small amount of chemical or sterile product is being transferred to another vessel.
A variety of options for hypodermic needles are available:
- Length: A typical range is from 0.5 to 5 or more inches; the length required is application-dependent
- Diameter or bore*: Indicated by gauge (g); usually from 10 to 34 (2.693 to 0.051mm); the size decreases as the gauge number increases
- Wall thickness*: Dimension between the external and internal diameters; can range from 0.05 to 0.4mm
- Dead volume: Amount of liquid contained in the needle lumen; an important factor when determining delivery volume
- Bevel: The angled end on the needle point; range from 12o to as much as 30o or 45o; may be single or tri-bevel
- Hub style: Luer lock, Luer slip, other specialty attachment; Luer connections are universal and adhere to ISO 594-2
- Hub material: Plastic or stainless steel
- Sterility: Available in sterile (often individually packaged), nonsterile; may be autoclavable
* An “s” next the gauge number indicates a slightly smaller internal diameter and a slightly thicker wall for more durability.
Safely dispose of used needles using a sharps container.