PEth testing for the family law courts

PEth testing for the family law courts

Phosphatidylethanol (PEth) testing is regularly relied upon in family law courts because it is such an accurate blood alcohol test.  

If parental alcohol misuse is a concern and a child may be unsafe in its own home, care proceedings will be initiated. In these types of cases, accurate alcohol testing is essential for decision making. PEth testing can uncover the pattern and extent of alcohol misuse to help assess the risk to the child. PEth testing can also be used to prove abstinence.

PEth is the most accurate blood alcohol test

PEth is the most accurate of the blood tests to determine alcohol abuse because it is a direct marker of alcohol; and as a result, it is one of the most popular alcohol tests ordered by family law courts. It is formed on the surface of red blood cells when ethanol reacts with phosphatidylcholine. This means that it can only be detected when alcohol has been consumed.

PEth production 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.

Because PEth is a direct biomarker of alcohol, it is a highly reliable blood test for alcohol abuse. Drinking experiments show that 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 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, patterns of alcohol consumption and identify relapse.

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, which can greatly help in family law cases when quick decisions are often vital.

Getting the right alcohol test for your case

AlphaBiolabs offers a wide variety of alcohol tests to choose from depending on the required timescale of alcohol assessment. As well as blood tests, the range includes instant breath tests and 3- or 6-month hair analyses to show alcohol consumption over a period of time. Continuous results are also available using an innovative alcohol monitoring bracelet.Our in-house toxicologists will be able to advise you on the best test for your particular case. We also offer a Comprehensive Alcohol Analysis Package that combines hair (EtG and FAEE), blood tests, Statement of Witness and sample collection. For expert advice or further information on legal alcohol testing for the family law courts, please call 0333 600 1300 or email us at

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