Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test


Carbohydrate Deficient Transferrin (CDT) is a biomarker for heavy alcohol consumption and is used by the DVLA in its fitness-to-drive test for high risk offenders.

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Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test

About this test

Why take this test?

  • you have received a driving ban and are reapplying for your license from the DVLA
  • you want to make sure that you will pass the DVLA medical
  • you want to use this test as proof that you have ceased or reduced your alcohol consumption

The Carbohydrate Deficient Transferrin (CDT) test measures a particularly sensitive biomarker that tracks heavy alcohol consumption over an extended period of time. If an individual drinks steadily and heavily (4-6 units of alcohol per day) for several weeks the percentage of transferrin which is deficient in carbohydrate will rise. The longer a person drinks at this level, the higher the level of CDT. Intermittent or binge drinking can also increase CDT levels. The extent to which this occurs is dependent on the frequency of binges and the amount of alcohol consumed on each occasion.

Elevated CDT will decline with reduced alcohol consumption, and will revert to normal after several weeks of abstinence.

This test has a very high level of specificity (i.e. it is not affected by other drugs or substances) and therefore it has been adopted by the Secretary of State's Honorary Medical Advisory Panel as the sole test for assessing harmful use of alcohol for high risk offenders. 

Who is this test for?

This test is for people who wish to prove that they have moderated or ceased their alcohol consumption. It is used by motorists who have been deemed high risk offenders to gain peace of mind before they take a CDT test as part of the DVLA medical examination to get their driving license back.

How it works

Collect Sample

We send you an easy-to-use kit to collect your blood sample.

Post Sample

Post your sample to our lab in the prepaid envelope provided.

View Results

View results securely in your own personal dashboard.

Important Information

Our tests are not a substitute for seeing your doctor, especially if you are suffering symptoms. Our doctors will interpret your results based on the information you have provided, but will not diagnose, consult or provide any treatment. You will be advised to see your doctor for any necessary follow-up action.

Tests Included

Drug & Alcohol

Blood sample collection kit

We will send you your Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test blood sample collection kit together with the details of a convenient clinic where you can go and have your sample taken.

Postage & packaging

Your Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test includes 1st class postage and packaging for you to send your blood sample directly to our laboratory for analysis. If you live in an area where you cannot rely on the post or you simply want to ensure that your sample arrives at the laboratory the following day, you may wish to send your blood sample guaranteed next day delivery for extra reassurance.

Private laboratory analysis

Your blood sample will be analysed at one of our chosen laboratories. You can be assured of fast, accurate results from one of our accredited independent providers of clinical diagnostic tests.

Interpretation of results

Our medical team will comment on out-of-range blood results and give you follow-up advice where necessary. If you need it, a PDF copy of your Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test results can be downloaded for your doctor.

Secure online account

Once you have placed your order you can visit where you can manage your account, track your orders and view your Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test results.

Health and Lifestyle tracker

Stay motivated by filling in your online health and lifestyle questionnaire and seeing how improvements in your lifestyle can influence your results. Your medical and family history gives us vital information when interpreting your results.

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