Carbohydrate Deficient Transferrin (CDT)

Carbohydrate-deficient transferrin (CDT) is measured by taking a sample of a patient's blood. Apparently healthy individuals with no or low reported alcohol consumption and a negative Alcohol Use Disorder Identification Test will have a %CDT <3.0 . Elevated levels of CDT suggest recent alcohol abuse, especially if other liver-associated enzymes (such as γGT) are elevated. Although recent heavy alcohol use is most commonly associated with elevated CDT, certain rare liver disorders can also increase levels of CDT. Various forms of transferrin exist, with differing levels of sialylation. The most common form is tetrasialotransferrin, with four sialic acid chains. In persons who consume significant quantities of alcohol, the proportion of transferrin with zero, one, or two sialic acid chains is increased. These carbohydrate-deficient transferrins can be measured in the bloodstream, and are an important marker for alcohol abuse.