Carbohydrate-deficient transferrin isoforms measured by capillary zone electrophoresis for detection of alcohol abuse

Background: Measurements of carbohydrate-deficient transferrin (CDT) are used as markers of alcohol abuse. We developed a capillary zone electrophoresis (CZE) method aimed at improving accuracy of CDT testing. Methods: We studied 111 alcohol abusers with Alcohol Use Disorders Identification Test scores >11 and 50 teetotalers. CZE was performed with a P/ACE 5500, fused-silica capillaries, and a CEofix CDT reagent set. After iron saturation, sera were loaded by low-pressure injection, separated at 28 kV, and monitored at 214 nm. We identified the transferrin isoforms by migration times, treatment with 100 U/L neuraminidase, and immunosubtraction with anti-human transferrin and anti-C-reactive protein antibodies. We compared CZE results with current biological markers of alcohol abuse, including the %CDT turbidimetric immunoassay. Results: Migration times of the isoforms were identical in both populations. Asialotransferrin was missing in teetotalers but present in 92% of alcohol abusers. Disialotransferrin was higher in those who consumed excessive amounts of alcohol, whereas mean trisialotransferrin concentration was not affected by alcohol abuse. At cutoffs to maximize sensitivity and specificity, these values were 0.92 and 1 [mean ROC area (MRa), 0.96; 95% confidence interval (CI), 0.93-0.99] for asialotransferrin; 0.84 and 0.94 for the sum of asialo- + disialotransferrin (MRa, 0.94; 95% CI, 0.91-0.98); 0.79 and 0.94 for disialotransferrin (MRa, 0.89; 95% CI, 0.84-0.94); 0.62 and 0.53 for trisialotransferrin (MRa, 0.58; 95% Cl, 0.49-0.68); 0.79 and 0.82 for a 3% %CDT, and 0.83 and 0.69 for a 2.6% cutoff (MRa, 0.87; 95% CI, 0.81-0.92). Current markers lack sensitivity (<0.65). Transferrins were not significantly correlated with serum enzymes and mean erythrocyte volume. Conclusions: CZE-isolated desialylated transferrin isoforms allowed differentiation between chronic alcohol abusers and teetotalers. (C) 2002 American Association for Clinical Chemistry.