Test Catalog

Test Id : CDTA

Carbohydrate Deficient Transferrin, Adult, Serum

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

Indicating chronic alcohol abuse


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


Patients with chronic alcoholism demonstrate increased levels of carbohydrate deficient transferrin over the amount of normally glycosylated tetrasialotransferrin.

Method Name
A short description of the method used to perform the test

Affinity Chromatography/Mass Spectrometry (MS)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Carb Def Transferrin, Adult, S

Lists additional common names for a test, as an aid in searching

CDT (Carbohydrate Deficient Transferrin)

Transferrin for Carbohydrate Deficient Transferrin (CDT)

Transferrin Isoforms

Specimen Type
Describes the specimen type validated for testing


Ordering Guidance

This test is for evaluation of alcohol abuse. If the ordering physician is looking for congenital disorders of glycosylation, order CDG / Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum.

Necessary Information

1. Patient's age is required.

2. Reason for testing is required if patient is younger than 21 years of age.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.1 mL


If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.05 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 45 days
Refrigerated 28 days
Ambient 7 days

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

Indicating 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)

Provides information to assist in interpretation of the test results

Patients with chronic alcoholism may develop abnormally glycosylated transferrin isoforms (ie, carbohydrate deficient transferrin: 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.

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 one 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 (CDG). 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. Shibamoto A, Namisaki T, Suzuki J, et al: Clinical significance of gamma-glutamyltranspeptidase combined with carbohydrate-deficient transferrin for the assessment of excessive alcohol consumption in patients with alcoholic cirrhosis. Medicines (Basel). 2021 Jul 19;8(7):39

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

Method Description
Describes how the test is performed and provides a method-specific reference

This method is a qualitative assay that measures transferrin isoform ratios using a combination of immunoaffinity capture and liquid chromatography-mass spectrometry analysis.(Lacey JM, Bergen R, Magera MJ, et al: Rapid determination of transferrin isoforms by immunoaffinity liquid chromatography and electrospray mass spectrometry. Clin Chem. 2001; Mar;47(3):513-518; Helander A, Wielders J, Anton R, et al: Standardisation and use of the alcohol biomarker carbohydrate-deficient transferrin [CDT], Clin Chim Acta. 2017 Apr;467:15-20 doi: 10.1016/j.cca.2017.03.018)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.


Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

7 to 10 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 month

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CDTA Carb Def Transferrin, Adult, S 53803-3
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
31714 Mono-oligo/Di-oligo Ratio 35469-6
31715 Interpretation 59462-2

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports