Test Catalog

Test ID: CDTA    
Carbohydrate Deficient Transferrin, Adult, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

An indicator of chronic alcohol abuse


This test is not appropriate for screening patients for congenital disorders of glycosylation.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Chronic alcoholism causes a transient change in the glycosylation pattern of transferrin where the relative amounts of disialo- and asialotransferrin (carbohydrate deficient transferrin: CDT) are increased over the amount of normally glycosylated tetrasialotransferrin. This recognition led to the use of CDT in serum as a marker for chronic alcohol abuse.


CDT typically normalizes within several weeks of abstinence of alcohol use. However, it is important to recognize that there are other causes of abnormal CDT levels, which include congenital disorders of glycosylation and other genetic and nongenetic causes of acute or chronic liver disease.


CDT testing alone is not recommended for general screening for alcoholism; however, when combined with other methods (ie, gamma-glutamyltransferase, mean corpuscular volume, patient self-reporting, ethylglucuronide analysis), clinicians can expect to identify the majority of patients who consume a large amount of alcohol.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

< or =0.10

0.11-0.12 (indeterminate)

Interpretation Provides information to assist in interpretation of the test results

Patients with chronic alcoholism may develop abnormally glycosylated transferrin isoforms (ie, carbohydrate deficient transferring: CDT >0.12). CDT results from 0.11 to 0.12 are considered indeterminate.


Patients with liver disease due to genetic or nongenetic causes may also have abnormal results.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This assay has not been fully validated for the investigation of alcoholism.


Carbohydrate deficient transferrin (CDT) testing alone is not recommended for general screening for alcoholism. Analysis of more than 1 biomarker is recommended to avoid misinterpretation of results.


The abnormal transferrin isoform pattern in patients with chronic alcoholism is similar to that observed in congenital disorders of glycosylation (CDGs). However, unlike most patients with CDG, the relative amount of monoglycosylated transferrin is much lower. Other conditions such as hereditary fructose intolerance, galactosemia, and liver disease may result in increased levels of CDT. In addition, preanalytic variables such as bacterial contamination may cause falsely elevated CDT values. Several factors may cause variability in CDT analysis, including: ethnicity, gender, pregnancy, body mass index, smoking, blood pressure, iron metabolism, drug interactions, chronic medical illness.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. De Giovanni N, Cittadini F, Martello S: The usefulness of biomarkers of alcohol abuse in hair and serum carbohydrate-deficient transferrin: a case report. Drug Test Anal 2015 Aug;7(8):703-707

2. Fleming MF, Anton RF, Spies CD: A review of genetic, biological, pharmacological, and clinical factors that affect carbohydrate-deficient transferrin levels. Alcohol Clin Exp Res 2004;28(9):1347-1355

3. Gough G, Heathers L, Puckett D, et al: The Utility of Commonly Used Laboratory Tests to Screen for Excessive Alcohol Use in Clinical Practice. Alcohol Clin Exp Res 2015 Aug;39(8):1493-1500

4. Stibler H: Carbohydrate-deficient transferring in serum: a new marker of potentially harmful alcohol consumption reviewed. Clin Chem 1991;37:2029-2037

5. Torrente MP, Freeman WM, Vrana KE: Protein biomarkers of alcohol abuse. Expert Rev Proteomics 2012;9(4):425-436