CDT Testing—Why You Should Test
Finding the chronic alcohol abusers in an insurance population of millions is a challenge you face every day. In a country where it is estimated that more than 200,000 Americans succumb to alcohol-induced premature death each year, it is imperative to detect those who abuse alcohol.

Carbohydrate-deficient transferrin (CDT) is an effective tool in the search for the chronic alcohol abuser. The CDT test is performed on serum samples in cases of suspected alcohol abuse.

When elevated, CDT can be indicative of chronic, excessive consumption of alcohol, defined as at least 60 grams of alcohol per day on a routine basis for a minimum of two or three weeks. Transferrin, a plasma glycoprotein that is responsible for carrying iron throughout the bloodstream, is synthesized in the liver. Transferrin usually contains four to six sialic acid molecules. Sialic acid is one of the many components of the carbohydrate (sugar) portion of transferrin. When an individual consumes excessive amounts of alcohol, the sialic acids that normally attach themselves to the transferrin are missing-thus the term, carbohydrate-deficient transferrin. CDT is also known as desialotransferrin (DST) in some medical literature.

Studies have found CDT to be a highly sensitive and specific indicator of excessive alcohol intake. Other causes of an elevated CDT measurement include biliary cirrhosis and obstructive liver disease. With the testing assay performed at LabOne, an elevated CDT is defined as greater than 6% of the total transferrin.

Recommended Testing Guidelines
CDT should be ordered in cases where there is a biochemical indicator of possible alcohol abuse. Examples are an elevated aspartate aminotransferase (AST) value or a high HDL cholesterol value.

It may also be a useful test when other underwriting information is obtained that indicates possible alcohol abuse. Examples are drunken driving citations in an MVR, a past history of alcohol abuse, or the presence of a disease or physical condition associated with alcohol abuse.