CDT Blood Test in London
Book a professional CDT blood test to help assess alcohol use over the previous 2-3 weeks. This test measures carbohydrate-deficient transferrin, a blood marker that may rise with prolonged or excessive alcohol consumption.
Results are usually available within 5 working days* and are delivered securely by email after doctor review.
Book Your CDT Blood Test
Overview of the Test
The Carbohydrate-Deficient Transferrin Test, commonly known as the CDT test, is a blood test used to help assess longer-term alcohol consumption. It is more useful than standard blood or urine alcohol tests when the aim is to review alcohol use over the previous 2-3 weeks.
CDT is a protein normally found in the body, so the result is not expected to be zero. CDT levels may rise in response to increased or prolonged alcohol consumption.
This test may be useful before a DVLA medical, or for personal, legal or workplace requirements. Results should be interpreted in the context of your health history and any requirements set by the requesting organisation.
Who Is This CDT Blood Test For?
This private CDT blood test is suitable for individuals or organisations that need documented testing for alcohol use over a longer window than standard alcohol testing.
DVLA Medical Preparation
Often used by people who want to understand their CDT level before attending a DVLA medical assessment.
Legal or Compliance Needs
May support legal, court or compliance requests where documented alcohol testing is required.
Workplace Testing
Suitable for occupational health or workplace alcohol testing requirements where CDT testing is requested.
Personal Monitoring
Helps assess alcohol use over recent weeks for personal awareness, recovery support or health-related discussions.
If you are preparing for a DVLA medical, consider booking your CDT test well before the appointment to allow time for results and reduce unnecessary anxiety.
Sample Type
This is a blood test carried out at Patient Reception in London. The sample is analysed for CDT, a marker linked to longer-term alcohol consumption.
How the CDT Test Works
The CDT test helps assess excessive alcohol consumption over the previous 2-3 weeks. It is different from standard alcohol blood or urine tests, which usually focus on very recent alcohol intake.
What It Measures
Carbohydrate-deficient transferrin, commonly known as CDT.
Detection Window
Helps assess alcohol use over approximately the previous 2-3 weeks.
Result Context
CDT is naturally present in the body, and the level may rise with increased alcohol consumption.
› Read more about CDT blood testing
Often Combined with Liver Function Testing
A CDT blood test is often combined with a liver function blood test to check liver markers that may be affected by excessive alcohol consumption over time.
Combining CDT with liver function testing may provide additional health context. A healthcare professional can advise whether this is appropriate for your situation.
Proof of ID Requirement
You must bring valid photo ID to your appointment to support traceability and professional testing standards.
Accepted ID
Passport or driving licence.
Not Accepted
Copies of ID or ID shown on a mobile phone.
Please bring original photo ID to your appointment.
Results and Turnaround Time
Results are usually processed within 5 working days* and securely delivered by email. All results are supervised by a doctor before being issued.
If you need the result before a DVLA medical or other deadline, book your test well in advance to allow for laboratory processing time.
Results cannot be provided over the phone because caller identity cannot be verified.
*Turnaround time may vary depending on sample collection time and laboratory processing.
Prefer to Test at Home?
If you would prefer not to attend Patient Reception in London, you can order a home CDT test kit instead. The home option allows you to collect a finger-prick blood sample and return it to the laboratory by post.
› Do a home CDT test instead
Why Choose Drug Test London?
Useful Before DVLA Medicals
Often chosen by people who want to understand their CDT level before a DVLA medical assessment.
Longer Alcohol Window
Helps assess alcohol use over approximately 2–3 weeks, rather than only the previous 1–2 days.
Secure Results
Results are delivered securely by email after doctor review and cannot be issued over the phone.
Book Your CDT Blood Test
Frequently Asked Questions
What does a CDT blood test show?
A CDT blood test measures carbohydrate-deficient transferrin. CDT is normally present in the body, but levels may rise with prolonged or excessive alcohol consumption.
How far back can a CDT test detect alcohol use?
CDT testing is commonly used to help assess alcohol use over approximately the previous 2-3 weeks. Detection and interpretation can vary depending on individual factors.
Is this useful before a DVLA medical?
Many people book a private CDT test before a DVLA medical to understand their CDT level in advance. You should still follow all official DVLA instructions for formal assessments.
Should I combine this with a liver function test?
A liver function test may provide additional information about liver markers that can be relevant in alcohol-related assessments. A healthcare professional can advise whether this is appropriate for your situation.
Do I need photo ID?
Yes. You must bring original valid photo ID, such as a passport or driving licence. Copies or ID shown on a mobile phone are not accepted.
How quickly will I receive results?
Results are usually processed within 5 working days and delivered securely by email after review. Turnaround time may vary depending on sample collection time and laboratory processing.
