Phosphatidylethanol

Phosphatidylethanols (Peth) are a group of phospholipids consisting of two fatty acid chains and one phosphate ethyl ester that are formed from phosphatidylcholine and ethanol by the erythrocyte membrane enzyme, phospholipase D.

PEth is formed only in the presence of ethanol. It can be detected in blood after 1 to 2 hours and for up to 12 days after a single bout of alcohol consumption. It is detectable for up to 28 days after the last drink with chronic heavy ethanol ingestion. Half-life is 3 to 5 days in adults. A concentration of 20 ng/mL or higher is evidence of moderate to heavy ethanol consumption.

PEth is a more sensitive biomarker for chronic ethanol consumption than carbohydrate deficient transferrin (CDT), ethyl glucuronide and ethyl sulfate. Since PEth can detect chronic and one-time alcohol consumption, it can be used to monitor alcohol consumption, abstinence and relapse. 

Method of detection is quantitative liquid chromatography/Tandem Mass Spectrometry. Specimen requirement is a lavender or grey top tube of blood or a dried blood spot. Blood tubes should be refrigerated.

References

Fleming MF et al. Phosphatidylethanol (PEth) detects moderate to heavy alcohol use in liver transplant recipients. Alcohol Clin Exp Res. 2017;41:857-862.

Jannetto PJ. Selecting and Interpreting Alcohol Biomarker Tests: Enough to Drive you to Drink. J Appl Lab Med. 2018;2:827-29.

Andresen-Streichert H. et al. Alcohol Biomarkers in Clinical and Forensic Contexts. Dtsch Arztebl Int. 2018;115(18):309-15.