Analysis of carbohydrate deficient transferrin serum levels during abstinence

An alcohol-associated change in the serum transferrin glycoform pattern, carbohydrate-deficient transferrin (CDT), is used as a biomarker of chronic moderate to heavy alcohol consumption. Furthermore, CDT is employed as a marker of abstinence. Here, we analyzed CDT in patients with chronic excessive alcohol abuse at the beginning and during abstinence. Twenty-nine alcohol dependent patients were recruited from an in-patient abstention program. Reported drinking levels were at least 100 g/d (range up to 450 g/d; mean: 248.9±94.7 g/d) within the last month before study entry. Blood samples were drawn at the beginning and during the abstention program and the relative concentration (%CDT) of CDT was determined using ion exchange followed by immunodetermination of CDT. At study entry, 25/29 patients had a %CDT level above the established cutoff. Although CDT levels declined during abstinence in most patients, in ten patients with %CDT levels just above the cutoff at the start of the program, the CDT values remained elevated 6 weeks after cessation of drinking. Our data indicate that %CDT levels below the cutoff cannot even rule out long lasting excessive alcohol abuse. Further, measurement of %CDT should be interpreted with special care when used as a marker of alcohol abstinence.