title: Kinetic measurement of the combined concentrations of acetoacetate and beta-hydroxybutyrate in serum.
abstract: This is an automated method for the kinetic measurement of the combined concentrations of acetoacetate and beta-hydroxybutyrate in a single channel of the "Multistat III" centrifugal analyzer. Acetoacetate is first reduced with high concentrations of NADH by catalysis with 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30). This reaction mixture is diluted with excess NAD+. The endogenous beta-hydroxybutyrate and that resulting from acetoacetate are then measured kinetically. Comparing the combined concentration of acetoacetate and beta-hydroxybutyrate (y) with the sum of acetoacetate and beta-hydroxybutyrate measured as described by Hansen and Freier (Clin Chem 1978;24:475) (x) yielded the relationship: y = 0.99x - 0.57 (r = 0.93, n = 25). The run-to-run CVs for low (5 mmol/L) and high (15 mmol/L) acetoacetate controls were 12% and 6%, respectively. The method is useful for determining the concentration of ketone bodies in 2-microL samples of serum of patients with diabetic ketoacidosis. The sensitivity can be increased to determine ketone body concentration in nonketotic individuals by increasing sample volume to 10 microL.
mesh_terms: D020155:3-Hydroxybutyric Acid; D000090:Acetoacetates / Q000097:blood*; D000328:Adult; D002384:Catalysis; D016883:Diabetic Ketoacidosis / Q000097:blood*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006884:Hydroxybutyrate Dehydrogenase / Q000378:metabolism; D006885:Hydroxybutyrates / Q000097:blood*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009243:NAD; D010072:Oxamic Acid / Q000494:pharmacology; D010084:Oxidation-Reduction; D011786:Quality Control; D012016:Reference Values; D013223:Statistics as Topic
chemical_list: D000090:Acetoacetates; D006885:Hydroxybutyrates; D009243:NAD; C016635:acetoacetic acid; D006884:Hydroxybutyrate Dehydrogenase; D010072:Oxamic Acid; D020155:3-Hydroxybutyric Acid