Evaluation of alcohol abuse. Carbohydrate Deficient Transferrin (CDT) testing alone is not recommended for general screening for alcoholism. The transferrin isoform pattern in patients with chronic alcoholism is similar, although not as strikingly abnormal to that observed in Congenital Disorders of Glycosylation (CDG). Conditions such as hereditary fructose intolerance, galactosemia, and other genetic or non-genetic causes of liver disease may also result in increased levels of CDT.