Can β-Hydroxybutyrate Be Detected at the Bedside by In Vitro Oxidation with Hydrogen Peroxide?

The diagnosis of ketoacidosis with an inordinately high plasma and urinary concentration ratio of β-hydroxybutyrate (β-OHB) to acetoacetate (AcAc) is difficult, because only AcAc and acetone react with the diagnostic reagents used clinically to detect ketones. The purpose of this study was to assess the validity of the claim that β-OHB can be identified with a simple modification of the usual bedside test for ketones, using hydrogen peroxide (H₂O₂) and Ketostix (Ames Division, Miles Laboratories, Inc., Elkhart, Indiana). Unfortunately, the lowest detectable concentration of urinary β-OHB was 50 mmol/L, and serum β-OHB could not be detected at levels less than 100 mmol/L, a clinically irrelevant level. The relative insensitivity, the inapplicability to serum, and the potential hazard of the routine use of 30% H₂O₂ by practicing physicians or houseofficers render the method of limited value.