Psychiatric assessment of patients with "20th-century disease".

wish to clarify the answer to 3 the question "Can alcohol swabs be used to clean the skin before the venipuncture is performed?" (Can Med Assoc J 1985; 133: 1154-1156). The answer "using an alcohol swab will not affect the blood alcohol concentration analysis..." is incorrect. I have found that alcohol on the skin at the time of venipuncture can contaminate the blood sample, a situation that arises if a large amount of liquid is swabbed onto the collection site and is still there when the needle punctures the skin. However, if the skin is swabbed with a minimum amount of liquid, which evaporates very quickly, then the skin is left dry at the time of venipuncture, and there is no contamination of the blood sample. Therefore, using an alcohol swab might affect the blood alcohol concentration analysis; nonalcohol swabs are advisable.