Enhanced clinical utility of gamma-CDT in a general population

The use of a combination of markers to detect excessive alcohol consumption has been reported to provide better sensitivity in the diagnosis of alcohol abuse than single markers. However, the optimal combination of markers for the diagnosis of alcohol abuse has not yet been found. The aim of this study was to compare the diagnostic value of carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) to discriminate among heavy drinkers (>280 g/week), moderate drinkers (105-280 g/week), and light drinkers (<105 g/week). Their mathematical combination, named gamma-CDT, which has been found to be a strong marker of alcohol abuse in a former study, was also evaluated.

The study was conducted in a group of 6962 subjects (3974 males and 2988 females), between the ages of 25 and 74 years, who participated in a large cross-sectional risk factor survey carried out in five geographic areas in Finland. In each study area, an age- and gender-stratified random sample was drawn from the general population. Sensitivity, specificity, positive and negative predictive values, and receiver operating characteristic curves were used to evaluate the performance of CDT, GGT, and gamma-CDT.

For both sexes, the combined marker had the highest specificity (95%) and sensitivity in detecting heavy drinkers. In all cases, gamma-CDT had the highest area under ROC plots. Our results also showed that GGT and CDT have similar, and rather low, sensitivity but high specificity in a general population.

Compared with single markers, a significant improvement of sensitivity was obtained when the combination of both markers was used, especially in females.