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Needle Sizes and Uses

Different Needle Sizes for Subcutaneous and Intramuscular Use
Needles are used to administer various medications. The length of the needle will depend upon the type of injection and the gauge size will depend upon the type of medication. Be sure to select the appropriate needle and adjust the size based on height and weight. For subcutaneous injections, a needle length between 3/8 to 5/8 of an inch should be used, while intramuscular injections are typically between 1 and 1.5 inches.
Adjust Size Based on Height/Weight
Different Size Needles for Different Size People

Needle sizes come in varying sizes because our patients come the same way. Remember to increase needle sizes for obese or larger patients and consider smaller needle sizes for thin patients or younger children.

Subcutaneous Injections

SUBQ injections penetrate through the dermis directly into the subcutanous tissue. They are often used for injections like insulin and heparin. Remember you can give SUBQ injections at 45 or 90 degrees in areas like upper arms, the abdomen, or anterior thighs.

3/8 or 5/8 inch
(3) Tree over 8 or (5) Hand over 8

You can always remember to use a smaller needle size for SUBQ injections like a 3/8 or 5/8 inch by remembering that you would never want a 3 inch long needle injecting into your abdomen.

Intramuscular (IM)

IM injections penetrate directly into the vascular muscles like the deltoid, ventrogluteal, or the vastus lateralis. Because of the depth of muscle beneath the subcutaneous tissue, remember to select a longer needle. Obese patients may require up to 3 inch long needles. Ouch!

1-1.5 inches
(1) Wand to (1) Wand (.5) Hand

Adults on average require needle sizes of 1-1.5 inches in length. Obese patients sometimes require up to a 3 inch long needle to penetrate the additional adipose tissue. Be sure to rememeber to consider a smaller needle for smaller patients like childen and thinner adults, especially those older elderly patients with atrophied muscles. These patients may only require a 1/2 to 1 inch needle to reach the muscle.

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