Final answer:
Alcohol needs to air dry on the venipuncture site to allow time for its antiseptic action and to avoid contaminating or diluting the blood specimen.
Step-by-step explanation:
When alcohol is used to cleanse the venipuncture site, it must be allowed to air dry prior to the stick because alcohol requires time for antiseptic action. Alcohols are bactericidal and fungicidal agents, effective in the disinfection of a broad range of vegetative microbes immediately after application due to their volatility. It is important for the alcohol to evaporate completely to provide the necessary antiseptic action and to avoid dilution of the blood specimen, which could affect the test results.