Comparison of serum beta-hexosaminidase isoenzyme B activity with serum carbohydrate-deficient transferrin and other markers of alcohol abuse.

We have compared beta-hexosaminidase (beta-Hex) activity, carbohydrate-deficient transferrin (CDT), mean corpuscular volume (MCV), gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values in serum from male alcoholic patients with the corresponding values in moderate and non-drinking subjects. The total beta-Hex activity was 2.5 times higher in the alcoholics than in the moderate drinkers and this increase was mainly due to a 5-fold increase in the activity of the B-isoform of the enzyme. This was expressed as a percentage of the total beta-Hex activity and called 'beta-Hex B%'. Strong correlations were found between alcohol consumption (g/ day) and beta-Hex B% (r = 0.757, P < 0.001, n = 42), alcohol consumption and CDT (r = 0.671, P < 0.001, n = 42), and beta-Hex B% and CDT (r = 0.628, P < 0.001, n = 57). Serum beta-Hex B% had a sensitivity of 94% and a specificity of 91% in detecting alcoholic drinking of > 60 g/day. As a single marker of alcoholic drinking, it was markedly more sensitive than MCV and the liver enzymes GGT, AST and ALT, and slightly more sensitive than serum CDT (94 vs 83%). At the CDT cut-off level of 20 U/l, 17% of the moderate and non-drinkers would have been classified as alcoholic drinkers and 17% of the alcoholics would have been classified as moderate drinkers. Some of these misclassifications were eliminated if the beta-Hex B% results were taken into account. We suggest that serum beta-Hex B% can be a useful and inexpensive laboratory test for alcohol abuse.