It has been known for some years that a partial deglycosylation of transferrin occurs in the sera of alcohol abusers. Different methods have been proposed in order to evaluate this carbohydrate-deficient fraction of serum transferrin. Chromatofocusing or isoelectric focusing followed by direct immunofixation have been used until now. Recently, a new method called the carbohydrate-deficient transferrin (CDT) test based on ion-exchange chromatography has been developed by Stibler et al. (Alcohol Clin Exp Res 10:535-544, 1986). Here we compare this new method with results obtained using our Tf index determination method. The upper limit of normal values was set to the 90th percentile of the values observed in a reference population. The population under investigation consisted of 50 healthy volunteers and 160 alcohol abusers whose ethanol consumption was evaluated through a questionnaire. Sensitivity and specificity of the CDT test have been found higher than 0.76 and 0.90, respectively. The correlation between both methods was 0.794, a satisfactory result considering that the CDT test and the Tf index do not exactly measure the same part of the carbohydrate-deficient transferrin. In a population of 23 patients with liver diseases not related to alcohol abuse, no abnormal CDT value was observed. We can conclude from these results that the CDT test now seems to be the best test to detect alcohol abusers.

We describe a technique for measuring carbohydrate-deficient transferrin (CDT) in serum. Serum transferrin fractions are separated by anion-exchange chromatography on microcolumns. Sialic acid-deficient transferrin fractions are collected in the eluate, and transferrin is then quantified by a rate-nephelometric technique. Imprecision (CV) was 4-5% within-run and 7-9% between runs (n = 15). Comparison with an isoelectric focusing-immunofixation method for transferrin index (x) yielded y = 761x + 7, Sy/x = 39 mg/L. Assay of sera from 90 abstainers or moderate consumers of alcohol showed that 81 (90%) had CDT concentrations between 30 and 70 mg/L. Among 74 alcoholics admitted to an alcohol treatment center, 54 (73%) had CDT > 70 mg/L, i.e., the diagnostic sensitivity was 73% at a specificity of 90% (area under receiver-operator characteristic curve = 0.891).

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