3-Penten-2-one, a novel aldehyde adduct, is a biomarker for increased acetaldehyde in urine.

Diagnostic profiling of urine for volatile compounds of around 400 patients using headspace solid-phase microextraction (HS-SPME) in alkaline conditions identified 3-penten-2-one (approximately 1 to >6.3 micromol/L) in 26 patients. Five were in barbiturate coma. 3-Penten-2-one, previously of unknown origin, was shown to be formed by aldol condensation of acetaldehyde with acetone or acetoacetate during analysis. Semi-quantification of acetaldehyde using in-fibre derivatisation HS-SPME, showed high concentrations in five urine (33-348 micromol/L) and two plasma (17 and 43 micromol/L) samples. Hence, urinary 3-penten-2-one is a useful biomarker for increased accumulation of acetaldehyde during abnormal metabolic stress.