Newswise — Des Plaines, IL - Researchers from the University of Wisconsin-Milwaukee and USDTL (United States Drug Testing Laboratory, Inc.) have published study results in the OpenOnline edition of the journal Addiction demonstrating the use of the direct alcohol biomarker ethyl glucuronide (EtG). Their results demonstrate EtG has promising ability to differentiate between various levels of alcohol consumption when analyzed in fingernail and hair specimens. Reinforcing earlier research, the study also demonstrated the effectiveness of EtG testing in alternate specimen types, especially fingernails, as an objective long-term alcohol biomarker. The results will be published in the print edition of Addiction in an early 2014 issue.

Ethanol is metabolically converted to EtG in the liver, which can then be captured within the keratin fibers of growing fingernails and hair. The detection of EtG in hair as a measure of chronic excessive alcohol consumption (as supported by the Society of Hair Testing) has become more prevalent in the drug and alcohol testing industry in the last decade. In 2011 USDTL developed an assay to analyze fingernails for the EtG metabolite. Scientists from USDTL secured funding from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) to compare the effectiveness of EtG analysis in fingernails to EtG hair testing. Researchers from the Center for Addiction and Behavioral Health Research at the University of Wisconsin-Milwaukee leant their expertise in alcohol and substance abuse research to the study.

The research examined paired fingernail and hair specimens from more than 600 students attending a Midwestern university. The students were surveyed for their drinking history - how often and how much they drank - over the 90 days prior to the study to establish the level of alcohol consumption associated with each set of samples. Fingernail and hair analysis is able to detect EtG that has been captured by the samples within the previous 90 days of growth. The study authors theorized college students would be more honest about their drinking habits because of a reduced stigma among their peers associated with drinking. Statistical analysis suggested that assumption was correct.

Based on their answers to the alcohol consumption survey, subjects were classified into one of three drinking categories: 1-14 drinks/week, 15-29 drinks/week, or 30 or more drinks/week. Each subject’s fingernail and hair specimens were then analyzed for the presence of EtG. The study authors statistically analyzed the assay results to see how effectively EtG analysis in fingernails and hair could identify alcohol consumption by subjects in each category.

The results demonstrated a very high efficiency of EtG analysis in both fingernail and hair samples to qualitatively identify any level of drinking. Fingernail analysis was 100% effective for identifying alcohol consumption in the highest category (more than 30 drinks/week, “high-risk” drinking as classified by NIAAA). Some indications from the study results also suggest that EtG analysis in fingernails may hold promise as a quantitative analytical tool to distinguish between the different levels of alcohol consumption, however, further research is necessary to develop this potential use of fingernail EtG testing.

Established in 1991, USDTL has made significant breakthroughs in detecting alcohol and other substances of abuse by developing assays in a wider variety of sample matrices. They offer a wide range of forensic testing services and specialize in hard to detect substances of abuse, alternative specimen types, and customized assays.

For more information on EtG analysis in fingernail and hair specimens please visit