What is a common needle gauge and length for subcutaneous injections?

• A. 25-27 gauge; 3/8-5/8 inch.
• B. 22-24 gauge; 1 inch.
• C. 25-27 gauge; 3/8-5/8 inch.
• D. 18-20 gauge; 1/2 inch.

Answer: (C)

Subcutaneous injections are delivered into the fatty tissue just under the skin, so using a thin needle and a short length helps minimize tissue trauma and avoid reaching muscle. A commonly accepted combination is 25 to 27 gauge with a length of 3/8 to 5/8 inch. The thin gauge reduces discomfort, while the 3/8 to 5/8 inch length is typically enough to reach the subcutaneous layer in most adults without penetrating muscle. Using a thicker needle (lower gauge) or a longer needle increases the risk of hitting muscle and causing more pain or changing how the medication is absorbed. Gauges like 18–20 with a 1/2 inch length are more suited to intramuscular injections, not subcutaneous ones, and a 22–24 gauge with a 1 inch length is also more commonly used for muscle injections.