Carbohydrate Deficient Transferrin (2)
Normal transferrin molecules contain 4 sialic acid residues. Chronic alcohol consumption causes a decrease in sialylation, leading to increased quantities of disialo- and asialotransferrin. Carbohydrate deficient transferrin (CDT) is used as a serum biomarker for chronic alcohol abuse. CDT typically normalizes within several weeks of abstinence of alcohol use.
It is important to remember that congenital disorders of glycosylation can also produce CDT. However, alcohol consumption increases the relative amount of monoglycosylated transferrin more than is seen in congenital disorders of glycosylation. Other conditions such as hereditary fructose intolerance, galactosemia, and liver disease may result in increased levels of CDT. Bacterial contamination of the specimen may also cause falsely elevated CDT values.
CDT testing alone is not recommended for general screening for alcoholism. CDT testing should be combined with gamma glutamyltransferase, mean corpuscular volume and ethylglucuronide analysis. clinicians can expect to identify the majority of patients who consume a large amount of alcohol.
Transferrin is purified by affinity chromatography and the relative quantity of carbohydrate deficient transferrin is detected by mass spectrometry. Normal level of CDT is <0.10.
Specimen requirement is a red top tube of blood.
