The effect of skin cleansing agents on ethanol results measured with the Du Pont automatic clinical analyzer

The effect of various prepackaged skin cleansers on the results of serum ethanol analyses performed with the Du Pont automatic clinical analyzer has not been previously reported. When added directly to serum in concentrations of either 0.625 or 1.56% (v/v), neither polyvinyl-pyrrolidone iodine nor benzalkonium chloride affected the ethanol results. The cross-reactivity of isopropanol with the automatic clinical analyzer ethanol procedure was 3.9%. The greatest interference in the measured ethanol concentration was from the addition of green soap tincture, which contained 30% ethanol. The effect of improper phlebotomy technique on ethanol measurements was also investigated by performing venipunctures through a pool of 100% ethanol on the skin. No ethanol was detected in these samples unless an ethanol-soaked sponge was pressed over the venipuncture site while the needle was withdrawn from the skin. When correct phlebotomy technique is used, skin cleansing agents should not affect the results of ethanol measurements determined with the Du Pont automatic clinical analyzer.