Carbohydrate Deficient Transferrin (CDT)
A specialist CDT blood test measuring Carbohydrate Deficient Transferrin, a biomarker used when assessing patterns of sustained heavy alcohol consumption.
Turnaround time
3 business days
Biomarkers count
1
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Overview of the Carbohydrate Deficient Transferrin (CDT) Test
The Carbohydrate Deficient Transferrin blood test measures CDT, a specialised laboratory marker associated with sustained high alcohol consumption.
The test assesses 1 alcohol-related biomarker: Carbohydrate Deficient Transferrin (CDT).
Transferrin is a protein produced mainly by the liver and is best known for transporting iron through the bloodstream.
Normally, transferrin molecules have carbohydrate side chains attached to them.
Sustained heavy alcohol exposure can interfere with this glycosylation process.
This increases the proportion of transferrin molecules with fewer carbohydrate groups, producing what is known as carbohydrate-deficient transferrin.
CDT is therefore different from measuring alcohol directly in the blood or urine.
Blood or urine alcohol testing reflects recent alcohol exposure.
CDT is used as a longer-window marker of sustained excessive intake, although the exact relationship depends on drinking pattern and individual biology.
It can be useful in occupational, clinical, medico-legal or treatment-monitoring settings where objective information about alcohol consumption is required.
CDT is relatively specific for sustained heavy alcohol use, but it is not completely unaffected by other factors.
Certain rare transferrin variants and selected liver or metabolic conditions can complicate interpretation.
The marker also does not reliably identify isolated episodes of binge drinking if heavy intake is not sustained.
A normal CDT result therefore does not prove complete abstinence.
CDT can be interpreted alongside Gamma-Glutamyltransferase, liver enzymes, Mean Cell Volume and other alcohol-related biomarkers where a broader assessment is required.
What Does the Carbohydrate Deficient Transferrin (CDT) Test Check?
The test measures carbohydrate-deficient forms of transferrin that can increase following sustained heavy alcohol consumption. This test measures 1 specialist biomarker.
Carbohydrate Deficient Transferrin (CDT)
Measures altered transferrin glycosylation associated with sustained high alcohol intake, providing a longer-window alcohol-use marker than a direct alcohol concentration.
Who May Benefit From the Carbohydrate Deficient Transferrin (CDT) Test?
CDT testing can be useful where objective laboratory information about sustained alcohol consumption is specifically required.
People undergoing alcohol-use monitoring - CDT can provide laboratory information about sustained heavy alcohol exposure.
People participating in an alcohol-reduction programme - Repeat measurements can help assess changes over time.
People requiring occupational alcohol assessment - Selected employment or safety-sensitive settings may request objective alcohol biomarkers.
People undergoing specialist liver or addiction assessment - CDT can complement liver enzymes and clinical history.
People with a previous raised CDT result - Repeat testing can help assess whether the marker is falling after reduced intake.
People requiring documentation of alcohol-use trends - Serial testing can provide more information than one isolated result.
People with abnormal GGT or liver enzymes where alcohol is one consideration - CDT can provide complementary information because the markers reflect different biological processes.
People advised to undergo CDT testing by a clinician or occupational-health professional - The result is most useful when interpreted for a defined reason.
How to Prepare
Do not deliberately change alcohol intake for a very short period solely to influence the result.
CDT is intended to reflect a sustained pattern rather than one isolated drinking episode.
Symptoms and Reasons to Consider the Carbohydrate Deficient Transferrin (CDT) Test
CDT itself does not cause symptoms. Testing is prompted by alcohol-use history, monitoring requirements or associated clinical findings.
A history of sustained high alcohol intake - CDT can provide objective laboratory information about longer-term excessive consumption.
A previous elevated CDT result - Repeat testing can help establish whether the marker changes after reduced intake.
Abnormal liver enzymes - CDT can complement GGT, ALT and other liver markers where alcohol exposure is relevant.
Participation in an abstinence or reduction programme - Serial results can contribute to structured monitoring.
Occupational monitoring requirements - Selected safety-sensitive or regulated roles may use alcohol biomarkers.
Clinical concern about harmful alcohol use - CDT can support assessment when interpreted alongside history and other laboratory findings.
The need for a longer-window marker than direct alcohol testing - CDT reflects a different timeframe from blood or urine ethanol.
Discordant alcohol-related biomarkers - CDT can add information when other markers and reported intake do not align.
CDT should not be interpreted as a perfect measure of how many units of alcohol a person consumes.
A normal result does not prove abstinence, and one raised result should be interpreted in the wider clinical and laboratory context.
Alcohol withdrawal can be medically dangerous in people with significant dependence and should not be attempted without appropriate support where dependence is suspected.
How to Book Your Carbohydrate Deficient Transferrin (CDT) Test
The CDT test can be booked privately for specialist laboratory assessment of sustained alcohol exposure.
Choose the Carbohydrate Deficient Transferrin (CDT)
Select the individual CDT blood test online.
Select your sample collection option
Choose an in-clinic blood draw or professional home or hotel phlebotomy where suitable.
Attend your appointment
A trained healthcare professional collects the required venous blood sample.
Laboratory analysis
Your serum undergoes specialist measurement of Carbohydrate Deficient Transferrin (CDT).
Receive your results securely
Your authorised result is delivered securely and can be interpreted alongside alcohol history and other liver or alcohol-related markers.
When Will I Receive My Results?
The specialist laboratory turnaround for Carbohydrate Deficient Transferrin is approximately 3 days after laboratory receipt.
CDT requires dedicated biochemical analysis rather than a routine direct alcohol measurement.
The sample undergoes laboratory measurement, quality-control procedures and result authorisation.
Turnaround begins when the specimen reaches the laboratory rather than necessarily from the exact time the blood sample is collected.
Understanding Your Results
The result reflects the proportion or concentration of carbohydrate-deficient transferrin according to the laboratory method.
A raised CDT result can provide evidence of sustained heavy alcohol consumption over the preceding period.
The result does not establish the exact quantity of alcohol consumed.
Different drinking patterns can produce different biological responses.
A result within the laboratory range makes sustained heavy consumption less likely within the marker's detection characteristics, but it does not prove complete abstinence or exclude occasional drinking.
CDT generally becomes more useful when results are compared over time.
A falling value following substantial reduction or abstinence can provide objective evidence of change.
Other biomarkers can answer different questions.
GGT reflects liver and biliary enzyme activity and can rise for several reasons unrelated to alcohol.
Direct alcohol tests reflect much more recent exposure.
The laboratory reference range and the specific reason for testing should therefore guide interpretation.
Why Book With London Blood Tests?
London Blood Tests provides private CDT testing for specialist alcohol-use assessment and monitoring.
Measures a recognised alcohol biomarker - CDT is associated with sustained high alcohol consumption.
Provides a different window from direct alcohol testing - CDT reflects longer-term biological changes rather than alcohol present at one particular moment.
Useful for serial monitoring - Repeat results can help demonstrate changes in sustained intake.
Can complement liver markers - GGT and other liver tests can provide additional information.
Useful in occupational and clinical assessment - CDT can be used where objective alcohol-use information is specifically required.
Specialist laboratory analysis - Samples undergo dedicated CDT measurement.
Professional blood collection - Clinic and suitable home or hotel phlebotomy appointments are available.
Clear pricing - The Carbohydrate Deficient Transferrin test costs £168.
Private Carbohydrate Deficient Transferrin (CDT) Blood Test in London
London Blood Tests provides private CDT testing for people requiring specialist assessment of sustained alcohol exposure.
The test costs £168 and assesses 1 specialist biomarker.
Results are expected approximately 3 days after laboratory receipt.
CDT is best used as an objective alcohol-use marker within a defined monitoring or clinical context rather than as a standalone measure of exact alcohol consumption.