EtG Testing
Ethyl Glucuronide (EtG) is a minor metabolite of alcohol. It is formed in vivo as a consequence of alcohol consumption. A small faction (0.02%) of a dose of alcohol is conjugated in the liver with glucoronic acid to form ethyl glucuronide. This compound is excreted in the urine. EtG can be detected in the blood for up to 36 hours and in the urine for up to five days after heavy alcohol use. A positive finding of EtG in the urine of an individual provides strong evidence that the person recently consumed alcohol, even if the alcohol itself is no longer detectable. Therefore, this compound is regarded as a biomarker of alcohol consumption and, potentially, relapses of alcohol use by an individual who is under restriction. Other biomarkers of alcohol use can be problematic since they can be influenced by age, gender, and a variety of other substances and non-alcohol associated disease. Fermentation may lead to false positives for alcohol since glucose and yeast may be present in the urine. This is especially possible if a urine sample is stored or shipped without refrigeration in warm weather. Since EtG is only created during the metabolism of alcohol, a false-positive test result due to external contamination cannot occur.