The aim of this study was to determine the efficacy of the combined use of carbohydrate-deficient transferrin (CDT) and the Early Detection of Alcohol Consumption (EDAC) test to assess heavy drinking in a population of males (n = 187) drinking an average of 20 drinks per day. Heavy drinkers (n = 138) and light drinkers (n = 49) were analysed in three ways: using the EDAC test alone, using the CDT test alone and using the EDAC and CDT tests combined. The EDAC method uses linear discriminant function to analyse a battery of routine laboratory tests that generate a score for each subject and its associated probability value. This translates into the likelihood of each individual being a heavy or a light drinker. CDT uses ion-exchange chromatography to extract CDT in the serum and quantifies it by radioimmunoassay. The EDAC alone showed 88% (122/138) sensitivity rate when identifying heavy drinking males and 98% (48/49) specificity rate when assessing light drinkers. The CDT test alone showed a sensitivity rate of 58% (80/138) and a corresponding specificity rate of 96% (47/49). When analysed in parallel, 92% (127/138) of heavy drinkers showed abnormal EDAC and/or CDT tests and 94% (46/49) of light drinkers were negative for both tests. When analysed sequentially, the CDT test confirmed 61% (75/122) of the heavy drinkers identified by the EDAC test. Specificity rate for this testing strategy was 100%, because the only false positives for EDAC tested negative for CDT. This preliminary study shows that EDAC and CDT may react independently to alcohol intake and can be combined for maximum diagnostic accuracy.