Why is it important to allow the alcohol to dry before making a venipuncture?

Allowing the alcohol to dry before performing a venipuncture is crucial primarily to prevent stinging and contamination of the sample. When alcohol is used for skin antisepsis, it works to kill bacteria and reduce the risk of infection at the puncture site. If the alcohol is not allowed to dry completely, it can mix with the blood when the vein is punctured, leading to a burning sensation for the patient. Additionally, the presence of residual alcohol can contaminate the blood sample, potentially affecting the results of certain tests, especially those that are sensitive to alcohol or those that require high precision in measurements. Therefore, letting the alcohol dry ensures both patient comfort and the accuracy of the blood sample collected.