NEPHELOMETRIC DETERMINATION OF CARBOHYDRATE-DEFICIENT TRANSFERRIN

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