LONGITUDINAL COMPARISON OF CARBOHYDRATE-DEFICIENT TRANSFERRIN AND GAMMA-GLUTAMYL TRANSFERASE: COMPLEMENTARY MARKERS OF EXCESSIVE ALCOHOL CONSUMPTION

The utility of carbohydrate-deficient transferrin (CDT) andgamma-glutamyl transferase (GGT) as biochemical markers of excessivealcohol consumption was studied in alcohol-dependent subjects.Serum samples were collected once weekly from 10 male out-patientsundergoing a 6-month alcohol treatment programme. Frequencyof relapse into drinking (defined as any intake of alcoholicbeverage) was assessed by self-reports during patient interviewsthree times per week and by daily determination of the 5-hydroxytryptophollevel in urine. A marked decrease in mean CDT and GGT valueswas observed during the initial month. Only one patient remainedtotally abstinent throughout the observation period, while fourhad sporadic relapses (2–5 days with alcohol consumption).Both CDT and GGT remained below the respective reference limitsin those patients. The other five patients drank more frequently(range 22–57 days) and increased their mean levels ofCDT and GGT after the initial decrease. As determined from thevalues at admission and during the course of the study, CDTappeared to be the most sensitive marker in six out of the 10patients. In one patient, both markers were affected in a parallelway, whereas two of those with frequent relapses responded toalcohol consumption with a marked increase in GGT, but withno or only a slight increase in CDT. One patient did not showany abnormal CDT or GGT values. In 54 female and 60 male serumsamples collected at random from patients during admission atan alcohol detoxification unit, 35% and 58% of the CDT valuesexceeded the reference limits for females and males, respectively.For GGT, 59% of the female and 67% of the male values were abovecut-off. Carbohydrate-deficient transferrin and GGT were notsignificantly correlated. Taken together, the present resultsindicate that measurement of both CDT and GGT will increasethe possibility of identifying excessive alcohol consumption.By following changes in CDT and GGT values during a period ofalcohol withdrawal, the most sensitive individual marker canbe determined. This in turn allows for improved detection ofrelapse into heavy drinking dunng long-term monitoring of out-patients.