Final answer:
The correct gauge for routine adult venipuncture is a 20 to 21 gauge needle, allowing for adequate blood flow and minimal discomfort.
Step-by-step explanation:
The appropriate needle gauge for routine adult venipuncture is typically a 20 to 21 gauge needle. This size is preferred because it is large enough to allow sufficient blood flow for most common laboratory tests while minimizing discomfort and the risk of hemolysis, which is the rupture of red blood cells. In contrast, a 16 gauge needle is often too large and used for blood donation, a 23 gauge needle might be used for small veins or pediatric patients, and a 30 gauge needle is too small for this purpose and used mainly for intradermal injections or insulin delivery. The correct answer is C. 20 to 21 gauge needle. When performing routine adult venipuncture, a 20 to 21 gauge needle is typically used. The gauge of a needle refers to its diameter, with a larger gauge indicating a smaller needle. In this case, the 20 to 21 gauge needle is suitable for collecting blood samples from adults as it allows for efficient blood flow and minimizes discomfort.