Effect of alcohol swabbing on capillary blood glucose measurements

A study was conducted to determine the effects of alcohol swabbing on reagent strip blood glucose (BG) measurements using Reflolux and Glucometer GX meters and the Exac Tech Pen. Sixty subjects were randomly allocated to one of the three meters. Each had three separate fingerpricks after either swabbing with 70% isopropyl alcohol and testing immediately or after drying for two minutes; or after no preparation; (n=180). BG was also determined at alcohol concentrations of 0%, 1%, 5%, 10% and 20% on hypo (1.2 mmol/l), normo (4.0 mmol/l) and hyperglycaemic ( > 28 mmol/) blood in vitro (six strips/meter/concentration, n=270). Increasing concentrations of alcohol caused reduction of BG at all glycaemias using the two meters (p= < 0.01) (ANOVA). At alcohol concentrations of 20% the pen showed an increase of 1.5 mmol/l at euglycaemia, and an increase of 2.7 mmol/l into the normal range at hypoglycaemia ( < 2 mmol). Alcohol concentrations of blood in vitro caused inaccuracies in reagent strip BG readings. The errors varied with the type of meter, decreasing with reflectance meters, and increasing with the pen. In practice, however, swabbing with alcohol prior to testing had no effect on meter accuracy in the clinical setting. Copyright © 1994 John Wiley & Sons, Ltd.