SENSITIVITY AND SPECIFICITY OF CARBOHYDRATE-DEFICIENT TRANSFERRIN AS A MARKER OF ALCOHOL-ABUSE ARE SIGNIFICANTLY INFLUENCED BY ALTERATIONS IN SERUM TRANSFERRIN - COMPARISON OF 2 METHODS

Despite a number of investigations suggesting the value of carbohydrat e-deficient transferrin (CDT) as a marker of alcohol abuse, a variety of issues on the applicability of CDT measurements in clinical setting s have remained unexplored. Earlier studies in this field have focused on the relationship of CDT and the amount of alcohol consumption or p resence of liver disease, whereas the influence of alterations in seru m transferrin concentrations on CDT has received less attention. In th is study, we compared two different methods for measuring CDT (CDTect and %CDT) and total transferrin concentrations in a sample of 83 alcoh ol abusers (20 patients with alcoholic liver disease and 63 heavy drin kers who were devoid of liver disease, despite excessive alcohol consu mption) and 89 controls, who were social drinkers or abstainers. The c ontrol population included 53 hospitalized patients with expected abno rmalities in serum transferrin concentrations caused by conditions suc h as negative iron balance, pregnancy, or nonalcoholic liver disease. Both methods gave significantly higher values in alcohol abusers than in controls (p < 0.01), but the overall sensitivity for detecting alco hol abuse was clearly higher for CDTect (59%) than for %CDT (34%). The correlation between the results obtained by the two methods (r = 0.62 9) significantly improved, when the CDTect values were replaced by the ratio of CDTect/total transferrin (r = 0.770) (p < 0.05). There was a positive correlation between the CDTect and serum transferrin (r = 0. 201, p < 0.01), which was significant both in the alcoholics (r = 0.24 0, p < 0.05), and especially in the controls (r = 0.727, p < 0.001), A significant inverse correlation emerged between %CDT and total transf errin (r = -0.302, p < 0.01), The sensitivities of CDTect and %CDT for correctly classifying alcohol abusers in the subgroup of alcoholic li ver disease patients were 90% and 70% and in the subgroup of heavy dri nkers without liver disease (49% and 22%), respectively. Specificities for CDTect and %CDT in this sample were 81% and 100%, respectively, H owever, in the subgroup of hospitalized control patients with abnormal serum transferrin, the specificity of CDTect was only 48%. According to present data, CDTect seems to be more sensitive than %CDT for detec ting alcohol abuse, However, any alteration in serum total transferrin concentration markedly decreases the assay specificity. This should b e considered when interpreting the assay results in patients with elev ated serum transferrin, such as iron deficiency, pregnancy, or liver d iseases.