COMPARISON OF DIFFERENT METHODS FOR DETECTING CARBOHYDRATE-DEFICIENT TRANSFERRIN

Different methods for detecting carbohydrate-deficient transferrin (CDT) were compared. In addition, their efficiency for detecting alcohol abuse among men not having clinical evidence of liver disease was studied in controls (n = 26), weekend (n = 16) end daily (n = 12) heavy drinkers, and alcoholics (n = 28). Comparisons were made between anion exchange separation of iron-saturated transferrin (Tf) by microcolumns (CDTect) and by the Fast Protein Liquid Chromatography (FPLC% and FPLC-MG), followed by double-antibody radioimmunoassay of collected fractions. Tf fractions with pl greater than or equal to 5.7 were also measured by two different isoelectric focusing (IEF) methods, followed by immunofixation (SA-IEF-CDT and IEF-CDT-TOT), the latter method being used also for detection of asialo-transferrin (IEF-CDT-AS). The cut-off was 20 units/liter for CDTect, 4.4% of total Tf for SA-IEF CDT, and the mean + 2 sd of the control group for FPLC-MG (as mg/liter of Tf), FPLC-%, IEF-CDT-TOT, and IEF-CDT-AS (all as percentage of Tf). The overall accuracies (combining sensitivity and specificity) for detecting heavy drinkers of CDTect, FPLO (mg/liter), FPLC (%), SA IEF-CDT, IEF-CDT-TOT, and IEF-CDT-AS were 63%, 59%, 61%, 74%, 57%, and 63%, respectively; for detecting alcoholics, 87%, 83%, 81%, 89%, 67%, and 76%, respectively. In conclusion, the methods were in rather good agreement with each other. Diagnostic characteristics among heavy drinkers and correlations between methods differed slightly, probably depending on the ability of different methods to separate and detect asialo-, monosialo-, and disialotransferrin. The overall accuracy among alcoholics was similar using each of the methods tested. The same was true among heavy drinkers, although SA-IEF-CDT had the highest sensitivity and overall accuracy among this group, making the method slightly better than the other ones.