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Test Identifier Information

Registration CodeSPEP

Capillary Electrophoresis - Charged molecules are separated by their electrophoretic mobility in an alkaline buffer with a specific pH.  Separation also occurs according to the electrolyte pH and endosmotic flow.

Diagnostic Use / Indications

Carbohydrate deficient transferrin (CDT) is most commonly used in adults for the assessment of chronic alcohol consumption. The test does not correlate with the amount of alcohol consumed, but relates to the prolonged consumption of large quantities of alcohol (>60g of alcohol per day over at least a week). A single episode of heavy drinking will not elevate CDT levels.

Note: 95% of individuals who either do not drink, or have normal drinking habits, have a %CDT of <1.7%. 5% of individuals will therefore have a %CDT of >1.7% without excessive drinking. (>60g of alcohol per day over at least a week). 

CDT has a long half-life of 15 days. Therefore under conditions of total abstinence it may take 1-2 months for %CDT levels to return to normal. It is therefore recommended that when monitoring patients trends be assessed over samples taken with intervals of 1-2 months.

CDT assessment of chronic alcohol consumption, should also be viewed infull clinical context and accompanied by the use of other tests to assist in the validation, in particular gamma glutamyl transferase should also be considered.

The factors listed below may interfere with the CDT assay and may disturb or prevent the CDT quantification:

  • Liver injuries (serious, end stage disease)
  • Aged or improperly stored samples
  • Anticoagulants
  • Fibrinogen and haemolysed samples
  • Monoclonal components or high polyclonal background 
  • Genetic transferrin variants
  • Carbohydrate deficient glycoprotein syndrome (CDG - rare)
External Price$75.98(Exclusive of GST)

Specimen Collection

Patient SpecimenPlain 5 - 10 mL (T15)

Instructions for Referral to CHLabs

Aliquot InstructionsMinimum 250 uL, Preferred 500 uL serum. Refrigerate. Plasma NOT acceptable.
Aliquot Transport to CHLOn ice or ambient

CHLabs Laboratory

DepartmentBiochemistry - Protein Laboratory
Contact Details Email Email
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Contact Phone Number(03) 364 0334 | x80334
Test AvailabilityBatched weekly
Turnaround Time1 week
Reference Interval
<1.3% CDT>1.3% - <1.6% CDT>1.7% CDT 



Results are reported as a percentage of total transferrin (%CDT) as this reduces the effects of gender and variation in levels of transferrin.


A CDT value of >1.7% is suggestive of chronic alcohol consumption.  It is strongly recommended that results be corroborated with other markers of excessive alcohol consumption. 

If CDT is elevated and gamma gluatmyl transferase (GGT) is also elevated this is strongly supportive of chronic alcohol consumption. If both GGT and CDT are low, the results would suggest that alcohol is probably not being misused. If only one indicator, either CDT or GGT is elevated and the other not, the result is inconclusive.

It is strongly recommended that CDT trends be monitored 1-2 months apart, due to the long half-life of transferrin (15 days), to determine the efficacy of therapy response.

Additional Information

For inborn errors of metabolism or assessment of transferrin variants in neonates (i.e. Carbohydrate deficient glycosylation, CDG) refer to Paediatric Biochemistry (03 364 0300 extension 80118).

Delphic Number Test Number8894

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