Carbohydrate deficient transferrin has been proposed as an important marker for alcohol abuse. Using isoelectric focusing and two different radioimmunoassays we measured carbohydrate deficient transferrin throughout an alcohol withdrawal period in ten abusing men. Values within the normal range were found in two to four individuals, depending on the method. Nevertheless, carbohydrate deficient transferrin was more frequent pathologically (in two out of three methods) than any other of the common markers (glutamyl transferase, alanine transferase, aspartate transferase, mean corpuscular volume). During the withdrawal period, the carbohydrate deficient transferrin value increased in two patients after a new alcohol intake. However, it also increased on other occasions when a new alcohol intake was highly unlikely. Therefore, a single test or even repeated tests of carbohydrate deficient transferrin may give a wrong conclusion. Since the cost of the analysis is high, the clinical benefit should be evaluated more closely before the test is used in pure clinical settings.