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PEth Testing in Dried Blood Spot

Uncover Patterns of Alcohol Use for Up to One Month

Introducing PEth: the most informative and valued-added test available for alcohol consumption. 

PEth (phosphatidylethanol) provides patterns of alcohol use for up to four weeks, not just detection, giving you a full month of past behavior for evaluation.


Breakthrough in Detection Windows:

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While PEth levels will start to rise after a single drinking episode, it is the accumulation of PEth that helps define past drinking behaviors. The PEth LCMS result falls into one of four general ranges for clinical consideration and interpretation. 

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PEth: A Scientific Overview

Phosphatidylethanol16:0/18:1 (PEth) is a group of phospholipids formed on the surface of an individual’s red blood cells when alcohol is consumed. The primary molecule (16:0/18:1) contains both palmitic acid (16 carbon atoms: no double bonds) and oleic acid (18 carbon: 1 double bond).  A secondary molecule (16:0/18:2) reflects the presence of two double bonds on the 18-carbon chain. The total homologues are identified using liquid chromatography/tandem mass spectrometry (LCMS) technology and thus evaluated for past alcohol patterns.   


Research has also shown that the highly sensitive nature of PEth is not affected by incidental exposures to alcohol such as mouthwash or sanitizers. National Labs carefully developed and validated specific lower thresholds in our method to avoid false positives and provide the most clinically useful information as possible. 

Dried Blood Spot (DBS): Convenient Collection 

A quick, painless finger prick provides a dried blood spot (DBS) specimen, which is all that is needed to measure PEth with the highest sensitivity of LCMS instrumentation. A DBS specimen can be collected by any properly trained staff or patient. Upon collection, the DBS is not considered a biohazardous material and is easily transported to National Labs.  

Testing with PEth is as easy as 1-2-3


1. Collect sample

Collect a dried blood test in- house (similar to a diabetes finger prick). Supplies provided by NL.

Save time and pre-register now, or register when you get to our testing site.

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2. Return package

Send to our lab via verified carrier.



Results in one-to-three days. 


National Institute on Alcohol Abuse and Alcoholism | Drinking Levels Defined

Wiley Online Library | The PEth Blood Test in the Security Environment: What it is; Why it is Important; and Interpretative Guidelines

National Library of Medicine | Phosphatidylethanol in Blood as a Marker of Chronic Alcohol Use: A Systematic Review and Meta-Analysis

Springer Link | Measurement of the alcohol biomarker phosphatidylethanol (PEth) in dried blood spots and venous blood—importance of inhibition of post-sampling formation from ethanol

Science Direct | Phosphatidylethanol Homologs in Blood as Biomarkers for the Time Frame and Amount of Recent Alcohol Consumption

Oxford Academic | Blood Phosphatidylethanol Concentrations Following Regular Exposure to an Alcohol-Based Mouthwash

National Library of Medicine | Phosphatidylethanol (PEth) detects moderate to heavy alcohol use in liver transplant recipients

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