Phosphatidylethanol (PEth) in Clinical Practice

Detection and Monitoring of Alcohol Consumption

Phosphatidylethanol (PEth) is superior to serum ethanol for detecting and monitoring alcohol consumption in clinical practice, offering a detection window of up to 12 days for a single drinking episode and up to 6 weeks for chronic heavy use, compared to the rapid clearance of serum ethanol within hours 1, 2
PEth detects a single drinking episode for up to 12 days and provides a semi-quantitative measure of chronic heavy alcohol use for up to 6 weeks 1, 2
PEth levels directly correlate with the amount of alcohol consumed, making it a quantitative biomarker unlike serum ethanol which only reflects current intoxication 1, 2
The American Association for the Study of Liver Diseases recommends using PEth for detecting recent drinking patterns and monitoring abstinence 1, 2

20 ng/ml (0.05 μmol/L) is the minimum reporting threshold for a positive test in US commercial laboratories 1, 2
18.5 ng/ml was found to be the optimal threshold for detecting heavy alcohol use (>7 drinks/week or >3 drinks/day for women; >14 drinks/week or >4 drinks/day for men) 1
A PEth range of 20-200 ng/ml (0.05-0.30 μmol/L) indicates alcohol use consistent with metabolic dysfunction and alcohol-related liver disease (MetALD), defined as 20-60 g/day or 140-420 g/week 2

PEth has higher specificity than indirect markers (GGT, AST, ALT, MCV) which can be altered by drug ingestion, liver disease, or muscle disease 1, 2, 3
PEth is not affected by compensated or decompensated cirrhosis, unlike carbohydrate-deficient transferrin (CDT) which becomes inaccurate in advanced chronic liver disease 1, 2, 3
The European Association for the Study of the Liver recommends using PEth as a first-line biomarker for detecting alcohol use due to its high specificity and reliability 1, 2

Use serum ethanol only when assessing acute intoxication or very recent alcohol intake (within hours) 1
Use PEth for detecting recent drinking patterns (past 2-6 weeks), monitoring abstinence, and quantifying chronic alcohol consumption 1, 2, 4
For liver transplant monitoring, serial PEth measurements are the preferred approach 1, 2