COMPARISON OF THE AXIS PERCENT-CDT-TIA AND THE CDTECT METHOD AS LABORATORY TESTS OF ALCOHOL-ABUSE

Carbohydrate-deficient transferrin (CDT) has been suggested as a speci fic marker of alcohol abuse. We designed this study to compare the con ventional CDTect method (Pharmacia & Upjohn) and the new semiautomated Axis %CDT turbidimetric immunoassay (%CDT TIA) for their diagnostic p erformance to identify problem drinking. The sensitivities of the %CDT TIA and CDTect for correctly classifying heavy drinkers (n = 90) were 29% and 59% with the thresholds currently recommended by the manufact urers, respectively. In the control group (n = 114), which included ho spitalized patients with abnormal serum transferrin concentrations, th e CDTect assay gave 21 false-positive values (18%), whereas the %CDT T IA showed 100% specificity. With the cutoff limits based on the presen t healthy control group (mean + 2 SD), the sensitivities of the %CDT T IA and CDTect were 61% and 86%, respectively. For men, the ROC plot ar ea of the CDTect results in comparisons of alcohol abusers and healthy controls was significantly (P < 0.05) higher than that of the %CDT TI A results, whereas for women, there was no significant difference in t his respect. The slope and intercept (with 95% confidence intervals) f or linear regression between CDTect and %CDT TIA were 0.13 (0.12-0.15) and 1.16 (0.73-1.59), respectively (S-y/x = 1.51, r = 0.744). CDTect results correlated positively with serum transferrin (r = 0.224, P < 0 .001), whereas the %CDT TIA results showed a slight inverse correlatio n with serum transferrin (r = -0.132, P = 0.07). The data suggest that CDTect is more sensitive than %CDT TIA in detecting drinking problems . However, the %CDT TIA method yields more specificity when analyzing samples from patients with high serum transferrin concentrations.