Final answer:
Alcohol is allowed to dry before venipuncture to minimize infection risk and prevent alcohol from entering the bloodstream, which could affect lab results. It also enhances patient comfort by preventing a stinging sensation during needle insertion.
Step-by-step explanation:
Before a venipuncture procedure, it is critical to allow the alcohol used for sanitizing the puncture site to dry completely. The primary reason for this is to minimize the risk of infection by ensuring that any potential pathogens on the skin surface are eradicated. Alcohol is a powerful antiseptic that, when applied to the skin, quickly works to destroy bacteria and other microbes that may cause infection once the skin barrier is breached by the needle.
Moreover, allowing the alcohol to dry also prevents the alcohol from entering the bloodstream, which could potentially affect laboratory results. As alcohol has a lower boiling point compared to water, it evaporates quickly at standard temperature and pressure (STP), which facilitates a rapid drying process. This quick evaporation prevents any significant amount of alcohol from remaining on the skin that could be introduced into the venous system during needle insertion. Additionally, undried alcohol on the skin might cause a stinging sensation to the patient when the needle is introduced, which can be avoided by letting the alcohol evaporate.
Drying the site properly thereby enhances patient comfort, reduces risk of contaminating the blood sample, and maintains the integrity of the blood specimen for accurate laboratory analysis.