What is a PEth test?

Phosphatidylethanols or “PEths”, are formed inside the body as a consequence of ethanol (alcohol) reacting with phospholipids in the membranes of red blood cells.

As PEth is a very specific alcohol biomarker, it is particularly effective for detecting chronic and heavy drinking.

It is a “dry blood spot” test, which involves obtaining a few drops of blood from the client’s fingertips. The PEth test results then reflect alcohol intake in the previous 3 to 4 weeks.

If the result is above the cut-off set by the laboratory, it indicates repeated heavy alcohol consumption in the previous couple of weeks.  

How much alcohol is too much alcohol?

The Limitations of a PEth alcohol test

The PEth Lab test cannot identify the exact amount of alcohol being consumed. Nor can it tell you the pattern of drinking. Therefore, a single PEth alcohol test will not give a full insight into drinking patterns and how long they persist.

While a negative PETH test, in which no PETH is detected, may suggest abstinence, isolated drinking events may not be detected, and thus the test cannot be used to confirm abstinence.

So how can a PEth test be used?

We would usually recommend that a PEth lab test be considered alongside other forensic testing or as a series of tests to review a sustained and meaningful period.

Blood alcohol tests should be combined with a hair alcohol test and medical interpretation to get the full picture of any alcohol misuse.

How is substance testing used in the family court?

What alcohol testing services are available?

Hair strand alcohol testing

If long-term drinking is a concern, then head hair alcohol testing and measurement of the biomarkers EtG and FAEEs can give an average result for the previous 3 or 6 months of drinking. A 3-6 cm sample of head hair is all that is required.

Blood alcohol testing

A blood sample alcohol test can also be used to assess the previous month’s alcohol intake. These alcohol tests look for CDT, as it’s the most specific marker for possible alcohol misuse. Other liver enzymes can also be affected by such alcohol intake.

Such a test may also show whether the individuals have other underlying causes. Blood alcohol tests can also reveal underlying health conditions or potential medical problems that a person may have.

What if a parent is unable to give blood for an alcohol test?

If the parent(s) are unable to give blood, then the PEth test reflects the amount of alcohol intake for the previous month. It is a highly specific and sensitive test, with results available within five days. 

See more articles on alcohol testing

How to get the fullest picture of alcohol consumption

If you’re looking for the full picture of alcohol use, it is always best to consider doing more than one type of test.

Another option could be to consider repeating the alcohol tests to monitor patterns of alcohol intake.

This way, you can identify if individuals are simply abstaining from alcohol long enough to skew the results. At Atkinson Lewis, we would recommend monitoring for at least six months—one year where alcohol misuse is a parental factor in child neglect.

Are Family Courts Seeing the Whole Truth in Drug and Alcohol Cases?

The Drug & Alcohol Laboratory Report that Offers a Medical Interpretation

At Atkinson Lewis, we are in the unique position of being able to offer a medical interpretation of results. Our experts are able to give a fuller picture in the laboratory reports thanks to their experience in the field of diagnosing and treating alcohol misuse.

What is included in the medical interpretation of the drug and alcohol tests?

We clinically interpret the results. Including noting any prescribed medications that are used to treat alcohol dependency or associated psychological problems.

We can also identify any potential liver disease which may be associated with harmful drinking. If required we can also offer an opinion on the potential pattern of drinking and advice on further assessment and treatment.  

For more information on alcohol testing and other services we provide, please contact us.