Aims: Carbohydrate deficient transferrin (CDT) is a common diagnostic marker for detecting chronic alcohol abuse. For over 2.5 years, it has been used in traffic medicine among subjects applying for driver's license renewal or regranting in Belgium. We report on data collected during the program and provide an estimation of an applicable cut-off point in forensic situations. Using this cut-off, the success of the driver's license regranting program is evaluated.
Methods: CDT was assayed at Ghent University Hospital by capillary zone electrophoresis, measured on the Capillarys 2™ system, in 3977 subjects applying for driver's license regranting. Determination of a cut-off was done by using Bhattacharya statistics and by adding a measurement uncertainty interval. The outcome of the program was evaluated by monitoring CDT values for 163 subjects during one entire year.
Results: In 3977 subjects (3481 males and 496 females), CDT values were significantly higher in men compared with women, but there is no need for a gender-specific cut-off value. Drunk drivers under the age of 30 have significantly lower CDT values than older subjects, and a separate cut-off could be calculated. A general cut-off of 2.3% CDT was calculated for the entire study population. Using this cut-off value for evaluating the outcome of the program for 163 subjects, the percentage offenders at the beginning (29%) decreased to 8% after 1 year.
Conclusion: Applying a marker for chronic alcohol abuse such as CDT for driver's license renewal or regranting is a powerful tool. Analysis of data collected over 2.5 years reveals a favorable outcome of the program and a useful cut-off point could be determined.