Intra- and interindividual variability of carbohydrate-deficient transferrin, gamma-glutamyltransferase, and mean corpuscular volume in teetotalers.

Blood samples for determination of the biochemical alcohol markers carbohydrate-deficient transferrin (CDT) in serum, gamma-glutamyltransferase (GGT) in serum, and erythrocyte mean corpuscular volume (MCV) were collected once every 1-2 weeks over approximately 5 months from 10 female and 4 male teetotalers. Mean values for serum CDT (using the CDTect assay) ranged from 9.9 to 29.4 units/L (median, 14.2 units/L), and the highest results were obtained in the women. The mean values for serum GGT ranged from 0.15 to 0.49 microkat/L (median, 0.30 microkat/L, or 18 U/L) except for one woman with a very high mean of 3.07 microkat/L. For MCV, the mean values ranged from 79.5 to 91.5 fL. Two women showed several CDT results above the upper reference limit (mean values, 27.6 and 29.4 units/L, respectively); however, their GGT and MCV values fell within the reference intervals. One of these women exhibited an increased total transferrin concentration (mean value, 5.38 g/L), which was possibly related to the use of oral contraceptives and/or a low serum iron concentration. When the CDTect value was expressed relative to total transferrin, a ratio within the reference interval was observed for this woman but not for the other woman with increased CDTect values. The present study demonstrates a considerable variation between individuals in CDT, GGT, and MCV without drinking any alcohol. The results also show that these baseline values are fairly constant over time within the same individual.