Elias D. Rady, Thomas G. Cotter
Accurate quantification of alcohol intake is essential for the diagnosis, subclassification, and management of steatotic liver disease (SLD). In everyday clinical practice, alcohol histories rely primarily on physician-assisted self-report, with validated questionnaires used variably. Both provider-level inconsistencies in documentation and patient-level factors (e.g., recall and social-desirability biases) can contribute to misclassification of SLD subtypes. Phosphatidylethanol (PEth), a direct alcohol biomarker detectable for ~2-4 weeks, has emerged as a promising objective tool that can complement self-report. Across diverse SLD populations, PEth consistently uncovers underreported alcohol use, sharpens subclassification, informs prognosis, and enables longitudinal monitoring to guide care. In liver transplantation, PEth supports documentation of abstinence and detection of relapse to enable timely intervention. This mini-review synthesises current evidence on PEth in SLD, emphasises its value in both clinical and research settings, and outlines priorities for integrating PEth into structured care pathways and clinical trial design to improve outcomes and harmonise endpoints.