For decades, primary care medicine has asked patients to account for their own drinking—through questionnaires and direct conversation—trusting that self-knowledge and honesty would surface those most at risk. A decade of Swedish health records now gently challenges that trust: a blood biomarker called PEth, which accumulates in proportion to alcohol consumed over recent weeks, reveals hazardous drinking in nearly one in seventeen patients who had already been cleared by standard screening. The finding is less an indictment of any single tool than a reminder that human self-report and biologic