Method-dependent characteristics of carbohydrate-deficient transferrin measurements in the follow-up of alcoholics

Aims: There are only limited data comparing the diagnostic characteristics of carbohydrate-deficient transferrin (CDT) measurements in assays for excessive alcohol consumption under controlled conditions. Methods: We compared different CDT assays and the conventional laboratory markers of ethanol consumption, gamma-glutamyl transferase (gamma-GT) aspartate aminotransferase (AST) and mean corpuscular volume (MCV) in the assessment and follow-up of 36 alcoholics (31 men, five women, mean age 44 years), who were admitted for detoxification. Detailed interviews to assess the amount of alcohol consumption were carried out for each patient. A hospital follow-up with supervised abstinence for 8 +/- 4 days (range 5-19 days) was carried out for 17 patients. Controls were 30 apparently healthy individuals (22 men, eight women, mean age 49 years), who had no history of hazardous drinking. Results: At the time of admission, the %CDT method, which excludes the trisialotransferrin isoform from the measurement, yielded elevated values in 69% of the patients, compared to 61% for CDTect. The corresponding sensitivities for gamma-GT, AST and MCV were 61, 56 and 47%, respectively. The self-reported alcohol consumption for a period of 1 month prior to admission showed a stronger correlation with the %CDT results (r = 0.59, P = 0.0003) than with the CDTect results (r = 0.36, P = 0.04), GT (r = 0.40, P = 0.02) or AST (r = 0.35, P = 0.05). During follow-up with supervised abstinence the mean %CDT values were found to show a slower rate to normalization (mean 14 +/- 4 days) than the CDT values measured with the CDTect method (mean 10 +/- 5 days) (P < 0.05). Conclusions: The data indicate distinct differences and method-dependent rates of normalization in CDT assays, possibly reflecting different degrees of transferrin desialylation in the alcoholics. The present findings should be considered in studies on alcohol markers for monitoring abstinence.