NCLEX-PN® ExaminationSafety and Infection ControlEasy
An LPN is preparing to administer a subcutaneous injection to a client. The LPN has drawn up 0.5 mL of medication. Which needle size is most appropriate for this injection?
- A20-gauge, 1-inch needle
- B18-gauge, 1 1/2-inch needle
- C22-gauge, 1/2-inch needle
- D25-gauge, 5/8-inch needle
Show answer & explanationAnswer & explanation
Correct answer: D. 25-gauge, 5/8-inch needle
Subcutaneous injections typically use a small gauge needle (25-30 gauge) and a short length (1/2 to 5/8 inch) to deposit medication into the subcutaneous tissue layer without reaching muscle. A 25-gauge, 5/8-inch needle fits these criteria.
Why the other options are wrong
- A. A 20-gauge, 1-inch needle is too large in gauge and too long for a subcutaneous injection; it is more suitable for intramuscular injections.
- B. An 18-gauge, 1 1/2-inch needle is too large in both gauge and length, typically used for drawing up viscous medications or for intramuscular injections in larger muscles.
- C. A 22-gauge, 1/2-inch needle is a possibility, but 25-gauge is generally preferred for less pain in subcutaneous injections, and 5/8-inch is a common standard length for adults if pinching the skin.
Subcutaneous Injection Needle Selection
The process of choosing the correct needle gauge and length for a subcutaneous injection, aiming to deposit medication into the adipose tissue layer beneath the dermis while minimizing pain and tissue damage.
- Gauge: 25-30 G (smaller numbers = larger diameter).
- Length: 1/2 to 5/8 inch (12-16 mm).
- Injection angle: 45 or 90 degrees, depending on client's body fat.
- Common sites: abdomen, outer aspect of upper arms, thighs.
Memory trick: Gauge Goes Small, Length is Short for SubQ