Fundamentals of Nursing Q 342
The appropriate needle size for insulin injection is:
A. 18G, 1 ½” long
B. 22G, 1” long
C. 22G, 1 ½” long
D. 25G, 5/8” long
Correct Answer: D. 25G, 5/8” long
A 25G, 5/8” needle is the recommended size for insulin injection because insulin is administered by the subcutaneous route. The board recommends 4-, 5-, and 6-mm needles for all adult patients regardless of their BMI. It is also recommended to insert 4-, 5-, and 6-mm needles at a 90-degree angle and that, if needed, longer needles should be injected with either a skinfold or a 45-degree angle to avoid intramuscular injection of insulin.
Option A: An 18G, 1 ½” needle is usually used for I.M. injections in children, typically in the vastus lateralis. Ensuring the correct delivery of insulin is essential in the treatment of diabetes. Both proper injection technique and needle length are important considerations for adequate insulin delivery. There have been several studies demonstrating that BMI does not affect efficacy or insulin leakage with shorter pen needles (e.g., 4 or 5 mm vs. 12.7 mm).
Option B: Additionally, the International Scientific Advisory Board for the Third Injection Technique Workshop released recommendations in 2010 on best practices for injection technique for patients with diabetes, which, with regard to needle length, concluded that 4-mm pen needles were efficacious in all patients regardless of BMI.
Option C: A 22G, 1 ½” needle is usually used for adult I.M. injections, which are typically administered in the vastus lateralis or ventrogluteal site. Needle lengths for subcutaneous injections started out as long as 16 mm in 1985, and 12.7-mm needles were introduced in the early 1990s. Over time, with growing evidence of longer needles increasing risks for intramuscular injections and improved technology, shorter needles of 4, 5, 6, and 8 mm have been developed.