Skip to content
Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test

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.
Blood sample 1 biomarker included Results estimated in 7 working days from sample receipt at lab
Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test
Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test
Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test
Carbohydrate Deficient Transferrin (CDT) DVLA Blood Test

Is it for you?

Have you been banned from driving and want to get your license back? Are you nervous about taking the DVLA test because you don't know if you've stopped drinking long enough to pass? Has heavy drinking been a problem for you in the past and you want to prove that you have not relapsed? If you want the reassurance of knowing that you'd pass the DVLA fitness-to-drive test, then this is the test for you.

What's included?

Biomarker profile

  • Alcohol Consumption

Alcohol Consumption (1 Biomarker)

From the expert

The Carbohydrate Deficient Transferrin (CDT) test measures a particularly sensitive biomarker that tracks heavy alcohol consumption over an extended period of time. Transferrin is a protein which carries iron to parts of the body that need it. Drinking too much alcohol can cause an increase in certain types of transferrin which are deficient in carbohydrate. 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.

Dr Sam Rodgers MBBS, MRCGP
Chief Medical Officer

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 stopped or reduced your alcohol consumption
  • You've been asked by your medical practitioner to take this test

Laboratories you can trust

Trusted by the NHS and private clinics alike, you can be sure of the highest testing standards from our UKAS accredited partner laboratories.

Dr Sam Rodgers - Chief Medical Officer

Expert advice with your results

Get trusted advice and comments from one of our doctors based on your results.

Your personal health centre

Your personal health centre

Discover the easy way to track your health through our online portal, View your results with doctor's advice, monitor any changes over time and see the improvements you can make to your health with simple lifestyle changes.

Questions? Let us help
Questions? Let us help

Questions? Let us help

Our customer care team is on-hand to help you find the test that's right for you. Get in touch via phone, live chat or email.


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.