What is PEth Testing?
PEth blood test quantifies the concentration of in a person’s blood. PEth is produced in the blood when there is a significant level of alcohol. It adheres to the membrane of red blood cells and it stays there until the blood cell dies.
Persons who have professional licenses may be required to PEth test during periods of probation after DUI arrests or other alcohol related incidents. This would include doctors, PA's, dentists but can also include anyone whose license is regulated by a state agency.
The PEth test is a long term marker. Recent alcohol ingestion can be verified by breath (BrAC), by blood alcohol concentration (BAC), or direct alcohol biomarkers in blood and urine, such as ethyl glucuronide (EtG) and ethyl sulfate (EtS). The Peth test is useful because it is a longer term marker of alcohol use extending over weeks.
A recent journal editorial describes the PEth test this way:
Phosphatidylethanol (PEth) is an accurate and specific biomarker that detects recent alcohol use.1 PEth testing can be performed on whole blood or dried blood spots, has a wide detection window of alcohol use within 2–4 weeks, and can provide an estimate on the level of alcohol consumption. As such, PEth has advantages over other markers of alcohol consumption such as breathalyzer or blood alcohol levels (window of detection is too brief), carboxy-deficient transferrin (inaccurate), or nonspecific markers such as serum gamma-glutamyl transpeptidases (insensitive and inaccurate).
Making the best use of testing for blood phosphatidylethanol
Musto, Jessica A.; German, Margarita N.; Lucey, Michael R
Therefore, in the last ten years, the use of phosphatidylethanol (PEth) has been proposed for identifying persons with hazardous drinking habits, such as binge drinkers, and/or persons with moderate drinking habits (i.e., exceeding 20 g of pure ethanol per day). Note: 20 grams of ethanol is about 7/10 of an ounce of alcohol which is about 2 beers, one IPA, one glass of wine - not much.
Phosphatidylethanol (PEth) in Blood as a Marker of Unhealthy Alcohol Use: A Systematic Review with Novel Molecular Insights
https://pmc.ncbi.nlm.nih.gov/articles/PMC10418704/
Are Peth Tests Admissible in Court?
PEth tests are admissible as long as the particular test introduced at trial has been proven scientifically valid and was properly performed. The standard that must be met to introduce Peth tests is generally called the Kelly/Frye test. This test requires that the scientific evidence must be based on a technique that is generally accepted as reliable in the relevant scientific community, and that the correct scientific procedures were followed in the particular case
The burden of proof to prove reliability is on the party introducing the scientific evidence. People v. Leahy, 8 Cal.4th 587 (1994)) While all scientific tests are subject to a screening for general acceptance and reliability. Certain tests are routinely accepted as scientifically valid, over the years generally accepted “science” has been disproven. Most defense attorneys will object to any opposing scientific evidence as a precaution since scientific dogma today may be simply odd history tomorrow. Gunshot striation and bullet identification is an area where scientific examination previously allowed an expert to declare a match but more recently experts have been limited to showing similarities. DNA on the other hand has increased in specificity and numbers such as “only one person ten billion” would randomly match this profile have been allowed.
PEth testing is relatively new although scientifically it has been relied for years by liver transplant teams, alcohol rehabilitation programs and employers.
Conclusion
PEth testing affects criminal probation, parole, medical and other professional licensing. Our lawyers are expert in the scientific challenges relating to blood alcohol tests. if you have a licensing case or criminal case that implicated blood testing and particularly a PEth test, call Daniel Horowitz for expert assistance.