Mean cell volume and gamma-glutamyl-transpeptidase as markers of drinking in working men.

The usefulness of serum-gamma-glutamyl-transpeptidase (gamma-GT) and mean cell volume (MCV) as markers of alcohol consumption was assessed in men in employment (266 company directors and 222 manual workers in alcohol-production firms) and in 34 male alcoholic patients. The correlations of admitted consumption with gamma-GT were 0.307 (directors) and 0.418 (manual workers) and with MCV 0.439 (directors) and 0.360 (manual workers). A man with an MCV of over 98 fl and a gamma-GT level above 50 i.u./l had a 62% chance of admitting to drinking over 450 g alcohol per week. Although the probability of being a heavy drinker increases progressively with elevation in both these tests, as screening tests they lack power, though false positives may be explained in party by inaccurate self-reports by both survey subjects and patients. For clinical purposes, however, the tests have a use in supplementing self-report and in following problem drinkers in outpatient treatment.