Test ID: CDTA
Carbohydrate Deficient Transferrin, Adult, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
An indicator of chronic alcohol abuse
Method Name A short description of the method used to perform the test
Affinity Chromatography/Mass Spectrometry (MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Transferrin for Carbohydrate Deficient Transferrin (CDT)
Transferrin Isoforms
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.1 mL
Additional Information:
1. Patient's age is required. Reason for referral is required if patient is <21 years old.
2. This test is for evaluation of alcohol abuse. If the ordering physician is looking for congenital disorders of glycosylation, order CDG/89891 Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross OK |
| Lipemia | Mild OK; Gross OK |
| Icterus | Mild OK; Gross OK |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 45 days |
| Refrigerated | 28 days | |
| Ambient | 7 days |
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 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 (CDG) and other genetic and non-genetic 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) clinicians can expect to identify 90% or more 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 transferring (CDT) testing alone is not recommended for general screening for alcoholism.
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 mono-glycosylated transferrin is much lower. Other conditions such as hereditary fructose intolerance, galactosemia, and liver disease may result in increased levels of CDT. In addition, pre-analytical 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 Provides recommendations for further in-depth reading of a clinical nature
1. Delanghe JR, De Buyzere ML: Carbohydrate deficient transferrin and forensic medicine. Clin Chim Acta 2009;406:1-7
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. Salaspuro M: Carbohydrate-deficient transferrin as compared to other markers of alcoholism: a systematic review. Alcohol 1999;19:261-271
4. Stibler H: Carbohydrate-deficient transferring in serum: a new marker of potentially harmful alcohol consumption reviewed. Clin Chem 1991;37:2029-2037
5. Stibler H, Borg S: Evidence of a reduced sialic acid content in serum transferrin in male alcoholics. Alcohol Clin Exp Res 1981;5:545-549
Method Description Describes how the test is performed and provides a method-specific reference
Transferrin is purified from serum using affinity chromatography. The chromatography is done using an antihuman transferrin antibody that has been coupled to POROS-aldehyde media. Serum is applied to the affinity column, which sequesters transferrin isoforms using pH 7.4 phosphate buffer saline. Transferrin isoforms (TrfI) are eluted from the affinity column with pH 2.5 100mM glycine/2% acetic acid buffer and concentrated on a C4 column, which is then washed with water/methanol/glacial acetic acid (97/2/1) to remove excess phosphate and other buffer components, which suppress mass spectrometer (MS) response. TrfI are eluted from the C4 column and introduced to the MS using methanol/ water/glacial acetic acid/TFA (94.5/5/0.5/0.04). The MS is operated in Q1 scan mode from 2,000 to 3,000 amu with a complete analysis time of 6.5 minutes. Relative quantitation of carbohydrate deficient transferring is achieved by comparing a-oligosaccharide transferrin and mono-oligosaccharide transferrin to di-oligosaccharide transferrin.(Lacey JM, Bergen R, Magera MJ, et al: Rapid determination of transferrin isoforms by immunoaffinity liquid chromatography and electrospray mass spectrometry. Clin Chem 2001;47:513-518)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Wednesday: 8 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
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's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
82373
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 31714 | Mono-oligo/Di-oligo Ratio | 35469-6 |
| 31715 | Interpretation | 59462-2 |
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