Having blood drawn is a fact of life. Nearly everyone experiences it at some point. Fear of pain and multiple needle sticks cause many people to cringe at the thought. Learning the types of needles used in phlebotomy can help allay these fears.
A butterfly needle is a short needle with a small diameter attached to a thin, flexible tube. The needle is flanked by two rubber wings that allow the phlebotomist to grip and move the needle with ease. The tube is attached to a rubber boot that attaches to the blood collection tube.
Butterfly needles come in 21, 23 and 25 gauge sizes. The larger the number, the thinner the needle.
Blood samples taken from the wrist, hand and foot are collected almost exclusively with butterfly needles. Individuals who have shallow veins, or those who are prone to anxiety or movement when blood is drawn, often benefit from butterfly needles.
Because the needle is attached to a tube and not directly to the collection tube, a patient can move with some degree of ease, and not jar the needle or sample out of place.
Despite its small diameter and unimposing appearance, butterfly needles do not always result in less pain to the patient. Butterfly needles are short, and multiple sticks may be required to hit a vein. Blood clotting within the tube is possible, and if this occurs, a re-stick of the patient is necessary.