hypothetical guessing that might explain the apparent volume contradiction:<br><br>1) The needle or catheter that was used to sample the blood alcohol level was directly contaminated with pure isopropyl during insertion and sampling. <br>combined with<br>2) isopropyl alcohol reacts more strongly by a factor of 10 with whatever reagent is used to test for ethanol levels in the blood.<br><br>If either or both of the guesses is correct then the concern with the minute amounts of isopropyl in an alcohol swab might make for an innaccurate reading of blood alcohol levels in a large individual.