PEth Improves Classification of MASLD, MetALD and Alcohol-Associated Liver Disease: Lancet Gastroenterology & Hepatology | September 2026

Introduction:

Distinguishing MASLD, MetALD and alcohol-associated liver disease (ALD) depends heavily on self-reported alcohol intake, which is vulnerable to underreporting. This prospective study evaluated phosphatidylethanol (PEth) as an objective biomarker to improve steatotic liver disease classification.

Key Findings:

Among approximately 3,000 participants, nearly 40% of individuals with a history of excessive alcohol use underestimated their intake compared with PEth measurements. Even among metabolically classified patients, clinically relevant alcohol exposure was sometimes missed by questionnaires.

PEth has an important advantage over indirect biomarkers because it is formed only in the presence of ethanol and reflects alcohol exposure over approximately 1–4 weeks.

However, PEth should complement rather than replace self-report. Combining PEth with AUDIT-C could target testing to patients with uncertain alcohol exposure while avoiding unnecessary testing in clearly low- or high-risk individuals.

Bottom Line:

PEth can substantially improve recognition of hidden alcohol exposure and help distinguish MASLD from MetALD and ALD. Its greatest value is as an adjunct to structured alcohol history, although optimal diagnostic thresholds and longitudinal testing strategies still require validation