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A PEth blood test is used to determine alcohol abuse. PEth is a direct marker of alcohol. This means that it is a highly accurate blood test because it can only be detected when alcohol has been consumed. Its high specificity (48–89%) and sensitivity (88–100%) is because it is directly related to alcohol consumption.

What is PEth?

PEth is short for phosphatidylethanol, which is an abnormal phospholipid produced after alcohol exposure in red blood cell membranes. It requires ethanol for its production and is formed on the surface of a red blood cell when the alcohol reacts with phosphatidylcholine.

The production of PEth begins as soon as ethanol is consumed and accumulates in blood with frequent alcohol consumption. The result provides a detection period of up to 3–4 weeks. However, the greater the exposure and/or larger the binge session(s), the longer the period of detection.

PEth blood tests are highly reliable

Because PEth is a direct biomarker of alcohol and requires ethanol for its production, it is a highly reliable blood test for alcohol abuse. PEth can be detected in blood after 1–2 hours and for up to 12 days after a single drinking episode. In addition, daily alcohol consumption of more than 60 g ethanol (7.5 units) can clearly be distinguished from lower alcohol consumption. As such, PEth testing can detect chronic and single-drinking episodes. It can also be used to monitor abstinence, drinking behaviour and identify relapse. PEth analysis can also verify whether an individual has changed their pattern of alcohol consumption.

In terms of all alcohol tests, PEth is second to the detection of ethyl glucuronide (EtG  – another direct metabolite of ethanol) in hair alcohol testing. However, PEth analysis has the advantage of allowing faster verification as to whether an individual has changed their drinking behaviour.

PEth blood test package

AlphaBiolabs recommends using a Comprehensive Alcohol Analysis Package to support any individual blood test result. This combines hair testing (EtPa [ethyl palmitate] and EtG) with four blood tests (Liver function test, carbohydrate deficient transferrin test, mean corpuscular volume index and PEth). It also includes a Statement of Witness report and sample collection. The Comprehensive Alcohol Analysis Package provides the best insight into an individual’s level of alcohol consumption.

As well as PEth blood tests and the other blood alcohol tests, AlphaBiolabs offers other alcohol testing solutions including instant breath tests, nail clippings, body hair and 3- or 6-month hair analyses to show alcohol consumption over a period of time. Real-time results are also available with SCRAM Continuous Alcohol Monitoring®. For expert advice on which alcohol test to choose, please call Customer Services on 0333 600 1300 or email us at