What type of needle is most commonly used for adult venipuncture?

The most commonly used needle for adult venipuncture is a 21-gauge needle. This gauge strikes a balance between being large enough to allow for adequate blood flow and small enough to minimize discomfort during the procedure. It is particularly suited for the majority of adult patients, facilitating the collection of blood samples efficiently without causing significant trauma to the veins.

The 21-gauge needle is versatile and is used in various testing situations where a standard volume of blood is required. Its size helps prevent hemolysis, which can occur with smaller gauge needles if blood cells are damaged during the draw, thereby ensuring the integrity of the sample collected for laboratory testing.

In contrast, smaller gauge needles, such as 25-gauge and 23-gauge, are more appropriate for pediatric patients or when collecting blood from fragile veins, and they may not provide the same efficiency in blood flow for adult venipuncture. The 18-gauge needle, while larger and allowing for rapid blood flow, is generally used for specific situations like blood transfusions or invasive procedures rather than routine blood draws.