Alcohol biomarkers as tools to guide and support decisions about intoxicated driver risk

This article describes the results of a pilot study that used alcohol biomarkers to guide decisions about driving under the influence (DUI) driver risk in the United States, replicating a European best practices model. The pilot tested whether biomarkers (1) can help the assessor identify high-risk drivers who continue to drink heavily after their arrest and (2) detect relapses in drivers enrolled in their drivers' safety plans.

These questions were addressed using two biomarkers, carbohydrate-deficient transferrin (CDT), and the Early Detection of Alcohol Consumption (EDAC) test, to evaluate the drinking behavior in repeat offenders during the assessment interview (baseline) and at 3, 6, 9, and 12 months' follow-up. The cutoff used to determine heavy drinking at baseline was 2.2 percent CDT and 40 percent P-positive for EDAC. A 30 percentage point increase in biomarker value from an abstinent baseline signaled a relapse and a 30 percentage point decrease in biomarker value from a previous positive measure signaled reduced drinking/abstinence.

The results show that the EDAC used alone identified 18 percent of drivers as heavy drinkers at baseline compared to 5 percent for CDT and 8 percent for GGT. The best detection rate was achieved with the EDAC-CDT combination, which captured heavy drinking in 20 percent of the repeat offenders at baseline, most of whom (68%) denied drinking at the assessment interview. During follow-up, 52 percent of drivers abstained/reduced their drinking, almost 20 percent experienced a relapse, and 30 percent remained noncompliant with testing. Drivers who relapsed were less likely to be employed full-time (67 versus 84%) or married (17 versus 30%) compared to those who abstained. Of the drivers who relapsed, 80 percent returned to abstinence or reduced their drinking after biomarker information was used as brief intervention by the counselors.

Biomarker testing improved the assessment and monitoring of repeat offenders in this pilot because it provided an objective tool to identify high-risk drivers allowing for better treatment recommendations and helped identified drivers who relapsed during follow-up to facilitate a brief intervention by the counselor that resulted in reduced alcohol consumption. These results contribute to establish evidence based practices in highway safety and are setting up new guidelines in the United States to reduce drunk driving.