Diagnostic clarity in matters related to alcoholism

Carbohydrate deficient transferrin (CDT)

The glycoprotein transferrin is synthesised in the liver. There are several isoforms, which differ from one another in that they have different numbers of carbohydrate chains, among other things. At the end of each of these carbohydrate chains, there is a sialic acid molecule. A healthy liver predominantly produces tetrasialotransferrin. Transferrins with less than four sialic acid residues (disialotransferrin, asialotransferrin, etc.) are known collectively as CDT.

CDT is produced by an alcohol-damaged liver instead of tetrasialotransferrin. It can be detected at a higher concentration in serum over a period of approximately two weeks after on-going high alcohol consumption of > 60 g / day (approx. 0.6 litres of wine or 1.5 litres of beer or 0.2 litres of spirits with an alcohol content of 40 % by volume). The concentration is dependent on the duration and seriousness of the abuse. One-time alcohol consumption does not lead to increased CDT values, nor even one time of excessive drinking. Compared to conventional parameters of alcohol abuse (MCV, Gamma-GT), CDT is characterised by greater specificity with the same sensitivity.

CDT is now recognized as the most specific biological marker of chronic alcohol abuse.

Half-life
Its half-life is approx. 10 days. Retrospective monitoring of alcoholics in therapy is therefore possible by a four-week determination of the CDT concentration. There is a close correlation between CDT concentration sampling and the duration of abstinence. After discontinuing alcohol consumption, the CDT values normalise within 2-4 weeks.

Indication

Detection of alcohol abuse, abstinence monitoring

Reference range
≤ 2.47 %

Serum test material
Serum

Storage life
7 days at +2 - +8 °C,
up to three months at -20 °C

Preanalytics

  • Avoid fatty foods before the blood sample is taken
  • Rapid transportation of samples to the laboratory

Notes

  • Non-alcohol-related severe liver diseases lead to false positive values.
  • Extremely high values are found in CDG syndrome (carbohydrate-deficient glycoprotein syndrome).


Literature

März, L., M. Hatton, L. Barryand, E. Regoeczi: The Structural Heterogeneity of the Carbohydrate Moiety of Desialylated Human Transferrin. Can. J. Biochem. 60: 624-630, 1982.
Stibler, H., S. Borg: Carbohydrate Composition of Serum Transferrin in Alcoholic Patients. Alcohol Clin. Exp. Res. 10: 61-64, 1984

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