Diagnostic of alcoholism: how useful is the combination of gamma glutamyl transferase with different biochemical markers?

The present paper analyses the alterations in sensitivity, specificity and in the positive predictive value (PPV) of GGT as a state marker of alcohol abuse when used either alone or in combination with glutamate pyruvate transaminases (SGPT), glutamate oxalacetate (SGOT) and mean corpuscular volume (MCV). The results obtained with an alcoholic (n = 70) and non-alcoholic sample (n = 63) showed that the best combination considering sensitivity was obtained when GGT was combined with MCV (80%). However, this combination produced the largest decrease in PPV. The relevance of taking into account not only sensitivity but also PPV when the markers are to be used as screening tests in unselected populations is discussed.