Urine and Breath Ketone Tests

Ketosis can cause false positives on some alcohol breathalyzers because acetone may be detected by alcohol-focused sensors. Urine strips detect acetoacetate spilled into urine rather than directly measuring circulating beta-hydroxybutyrate. Breath testing detects acetone, which the article describes as an exhaust-like ketone marker. Hydration and subjective color interpretation limit the precision of urine ketone strips. Breath ketone devices can be affected by false positives and sensor contamination from substances such as alcohol, sugar alcohols, lozenges, and gum.