PEth testing is the latest method of analysis for detection of recent alcohol use. Sampling is quick and convenient with results reported promptly.
Phosphatidylethanol (PEth) is a specific, direct alcohol biomarker, which forms only in the presence of ethanol. Testing for PEth is a more sensitive indicator than the indirect markers of CDT, LFT and FBE which can be influenced by other health issues and medications.
PEth indicates levels of alcohol consumption over a period up to 28 days. It takes approximately 28 days for PEth to be eliminated from the body. Because of this the window of detection is considered to be one month. The results are not impacted by age, gender, health status nor previous alcohol issues.
A small sample of blood is collected from the tip of the finger using a finger prick device, like a glucose test in your doctor’s office. The small incision enables collection of a blood spot that quickly dries. It is then sealed under chain of custody before it is sent for analysis by the laboratory. The dried blood spot is stable for PEth analysis and no special transport or storage required.
The sample required for PEth is less invasive.
Indirect markers CDT, FDT and FBE (carbohydrate-deficient transferrin, liver function and full blood examination) require a visit to a pathology clinic. At the clinic a sample of at least 5mL of blood is taken by a trained phlebotomist.
However, for a PEth test only four drops of blood are required. The test administered by a trained collector, in a convenient location such as a workplace or legal office. We have trained collectors available.
PEth testing can determine heavy, moderate or minimal alcohol use
The ability of a PEth test to distinguish between heavy, moderate and minimal alcohol consumption is a key benefit of the test. The levels that can be found in a sample are outlined below with their corresponding interpretation.
Abstinence or irregular low alcohol consumption in the approximate month prior to the sample collection.
PEth between 20 – 200ng/mL:
Consistent with alcohol consumption, but not at an excessive level, in the approximate month prior to the sample collection.
PEth >200 ng/mL:
Excessive alcohol consumption in the approximate month prior to the sample collection.
There are a few factors that affect the level of PEth such as differences in metabolism and frequency of alcohol consumption. The consumption of a higher number of drinks on one occasion will produce a higher blood alcohol concentration and consequently a higher PEth result than if the same number of drinks were consumed on five separate occasions.
It can take several weeks following abstinence from alcohol for all PEth to be eliminated from the body. The timeframe will depend on the original PEth level that existed for that individual.
Alcohol analysis can be enhanced by taking a hair sample and testing for ethyl glucuronide (EtG), a metabolite of alcohol. The EtG result, alongside the PEth analysis, can help determine if alcohol use is recent or long-term.
For more information see our PEth testing FAQ page.
Samples for PEth testing are sent to Cansford Laboratories with results returned within 1 – 2 weeks of sample collection. See Cansford’s blog for further information about PEth testing.