Dynamic Testing Solutions Blog

Hair and Nail Alcohol Testing

Hair alcohol testing measures average alcohol consumption over a period of approximately three months. This indicates the level of alcohol use during that time period and can provide a behavioral indication of excessive use. The hair test measures Ethyl Glucuronide (EtG), which is a trace metabolite of ethanol and is considered a direct alcohol biomarker. This test is used to provide answers about alcohol abuse and give an indicator of those dependent on alcohol. Fingernails are made up of keratin, the same material that hair is made of. As the nail grows, substances can pass from the blood vessels below the nail into the keratin fibers where they become trapped. Fingernails are four times thicker than the typical strand of hair and often capture more of a substance than hair can. Biomarkers become locked in keratin fibers along the entire length of the nail, and can be detected up to 3-6 months after drug or alcohol abuse. 

Ethanol is metabolized in the liver to produce EtG only when ethanol is in the body. Once t has been produced, EtG can be trapped and accumulated in the keratin fibers in the hair and fingernails. An EtG test in the hair and nails typically provides information on alcohol misuse over the past 3 months. Cutoff levels are set for EtG testing to eliminate the possibility of a positive results from accidental exposure such as use of mouthwash or ethanol based hand sanitizer.

Direct Alcohol Biomarkers

For hair and nail alcohol testing direct alcohol biomarkers EtG (ethyl Glucuronide) and PEth (phosphatidylethanol) are used when testing for alcohol use and alcohol abuse. Direct biomarkers are created when ethanol (ethyl alcohol) enters the body. Indirect biomarkers measure the effects of ethanol use on the health of the body. Even when ethanol is not present, indirect biomarkers may be formed. Unlike direct biomarkers, indirect biomarkers can be caused by factors such as hepatitis, liver disease, and other health issues. Whereas direct ethanol biomarkers can only produce positive results when ethanol is involved. This is why we use Direct Alcohol Biomarkers when testing for alcohol in the hair and nails.