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Hair strand testing is considered the gold standard in toxicological analyses. This long-established method can provide a history of drug and alcohol abuse and is routinely used in the forensic and family law fields.

Hair alcohol testing works by looking at two markers of ethanol: ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). The level of alcohol consumed will determine the level of these markers in the hair. Both types of markers are incorporated into the hair via different routes: EtG via sweat and FAEEs via sebum (an oily substance secreted by glands in the skin). By performing these two different types of hair analysis, our toxicologists can assist in building evidence to support the diagnosis of chronic excessive alcohol consumption with a greater degree of certainty.

Hair alcohol tests

Both EtG and FAEE markers are analysed because they are affected by external factors in different ways. EtG is water soluble, which means that some of the marker may be lost through excessive hair washing and the use of hair dye. FAEEs, on the other hand, are lipophilic (not water soluble), so although not affected by hair washing, the amount detected could be affected by the use of hairsprays, gels and wax, which contain alcohol.

It is possible to perform EtG analysis on hair samples collected from locations other than the scalp, such as pubic, underarm, chest, arm, leg, abdomen and beard. However, these tests have limitations. Pubic hair can be contaminated with EtG from urine.

Court ruling

Because of the respective strengths and weaknesses of EtG and FAEE tests, both tests should be performed and their findings should support each other in order to determine chronic consumption of alcohol. Indeed, as per the London Borough of Richmond vs. B & W & B & CB (2010) EWHC 2903 (Fam) case, the Court ruled that EtG and FAEE tests should always be used together. It went further saying that hair analysis findings should not be used in isolation but in conjunction with all evidence for the case including witness reports, other tests performed and any clinical assessments carried out. AlphaBiolabs always offers liver function and carbohydrate deficient transferrin blood tests wherever possible as supporting evidence.

Cut-off levels

Ideally, the minimum length of hair for EtG and FAEE tests is a 3 cm section taken from nearest the scalp, around 200 individual strands (about the width of a pencil). This is consistent with the consensus on hair alcohol testing for chronic excessive alcohol consumption published by the Society of Hair Testing (SoHT) in June 2009. The result will be considered either above or below the recommended SoHT cut-off levels. The level of biomarker found in the hair can help determine if a person has been drinking chronically and excessively, and will show an overview of 3 or 6 months. The results will not pinpoint exactly when the drinking occurred.

Unlike hair drug testing where the metabolites are absorbed through the root of the hair, when a client consumes alcohol the entire length of the hair will be contaminated with alcohol. Therefore, it is not possible to segment the hair. For example, if your client had not drunk for 2 months and then in 1 month drinks an excessive amount of alcohol, the alcohol markers will be found throughout the entire length of the hair.

In addition, abstinence cannot be established by means of hair alcohol tests. Research has shown that even individuals who have not consumed alcohol can test positive for both EtG and FAEEs. This can be explained because everyday foods can contain alcohol, and endogenous alcohol can be produced via normal human metabolism. For this reason, AlphaBiolabs would also recommend a blood test to detect alcohol biomarkers, in conjunction with clinical assessment, to gain a greater insight into an individual’s alcohol use. For expert advice or further information on legal alcohol testing, please call 0333 600 1300 or email us at info@alphabiolabs.com. AlphaBiolabs can test for alcohol in breath, blood, hair and nail samples. We also offer round-the-clock testing via SCRAM Continuous Alcohol Monitoring®.