The CDT assay is a marker of chronic alcohol consumption. This blood test can be requested by alcoholics or before a driver’s license is returned. What is the normal CDT level? How to calculate it? Bring it down? Is it reimbursed?
A high level of CDT (Carbohydrate Deficient Transferrin) reveals a excessive and chronic alcohol consumption. Dosing is done by blood test, without necessarily being on an empty stomach. People suspended from driver’s license must perform a CDT assay to recover their license. What is the standard rate of CDT? How the calculate ? How the bring down ? How much does it cost and is it reimbursed?
Definition: what is the CDT assay used for?
“CDT (For Carbohydrate Deficient Transferrin) East a protein found in the blood, that changes when a person consumes alcohol beyond WHO recommendations“, explains François Schellenberg, a biologist at the University Hospital of Tours. The dosage of CDT increases according to the quantity of alcohol absorbed.There is no absolute marker of alcohol consumption. CDT is the best we have in clinical routine. Nevertheless, the response of individuals will vary: about 25% of individuals are non-responders, their CDT does not increase with alcohol consumption“, notes the biologist.
What does the blood test for the CDT assay consist of?
“The dosage is done by a blood test, sent to a laboratory for analysis. We have the results after a few days“, explains François Schellenberg. There are about 180 laboratories that do this assay in France. This is not no need to fast to perform it.
What is the normal CDT level?
“The so-called ”normal” rate depends on the assay method. The International Federation of Biochemistry proposes a standardization protocol but for the moment, only 10% of French laboratories have chosen the standardized CDT“, regrets François Schellenberg. There is three methods, in addition to the standardized method, which give results ranging from simple to double. Each has its reference value. For the standardized method, the reference value is 1.7%. “A doctor who observes a higher value must ask himself“, adds the pharmacist. With other methods, the CDT rate should not exceed 1.3% or 2.6%. The modified protein has a half-life of two weeks in the body. For example, a value of 3.0% will decrease to about 2.2% after two weeks of weaning.
How to lower the CDT rate?
People who drink alcohol regularly and excessively have high CDT levels in their blood. The only way to lower the CDT rate is by alcohol abstinence for at least 15 days.
Is the CDT assay reimbursed?
The CDT assay is reimbursed by Social Securitythe regulatory rate is €14.85.
What rate of CDT to recover his driving license?
The CDT assay is used by driver licensing boards. After a driver has been tested with a positive blood alcohol level, he may be subject to a blood test to certify the chronicity of alcohol consumption. The departmental prefectural commissions can use the normalization of the biological assessment to proceed with the restitution of the driving licence. In this case, as a precaution, the upper limit is then raised to 1.7% in standardized value. To the assay of CDTs is added that of gamma GT, another marker of alcohol consumption or rather liver damage. “But gamma GTs are not a totally reliable marker. They are the witness of liver damage which can have other origins than alcohol consumption.…”, nuance François Schellenberg. THE VGM (Mean Globular Volume) can also be analyzed.
Are there false positives in CDT?
“False positives exist but they are extremely rare. They are due to a structural anomaly of the protein“, explains François Schellenberg. But if two methods are combined, including the reference method, it is possible to eliminate them. It should be noted that taking medication cannot lead to an increase in CDT.
Thanks to François Schellenberg, biologist at the University Hospital of Tours.