title: Enzymatic assay for conjugated bilirubin (Bc) in serum using bilirubin oxidase (BOD).
abstract: We described an automated enzymatic assay for conjugated bilirubin (Bc) in serum using the Iatro D-Bil kit, with bilirubin oxidase (EC 1.3.3.5 BOD) from Myrothecium species. The specificity of the enzyme in the Iatro D-Bil kit was examined by analyzing unconjugated bilirubin (Bu), delta bilirubin (Bdelta), and Bc with high-performance liquid chromatography (HPLC), before and after the enzymatic reaction using BOD. The within-assay coefficients of variation (CV) of this method were 0.58 to 5.00% (n = 20) at 1.4 to 155.8 micromol/L. Day-to-day Cvs ranged from 1.61 to 7.14% at 1.2 to 182.1 micromol/L. The analytical recovery was 96 to 101%. The presence of ascorbic acid, reduced glutathione, L-cysteine, uric acid, urea, creatinine, glucose, lipemic material, anticoagulants, hemoglobin, or human serum albumin did not affect this assay system. The correlation coefficient between values obtained with the Iatro D-Bil kit (y) and HPLC method as reference for conjugated fractions (x) was; r = 0.983, y = 0.952x + 8.851 micromol/L, Sy/x = 11.97 (n = 56). We studied serum Bc levels, not including Bu and Bdelta, in patients with hepatic diseases or autoimmune hemolytic anemia. Levels of Bc obtained by the proposed method changed more rapidly than did those of direct bilirubin (D-Bil) obtained by diazo-dye method during the course of the diseases.
authors.affiliation: Central Laboratory for Clinical Investigation, Osaka University Hospital, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kimura
authors.forename: S
authors.initials: S
authors.lastname: Iyama
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: S
authors.initials: S
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Yanagihara
mesh_terms: D000743:Anemia, Hemolytic / Q000097:blood; D001663:Bilirubin / Q000097:blood*; D006528:Carcinoma, Hepatocellular / Q000097:blood; D002624:Chemistry, Clinical / Q000379:methods; D002769:Cholelithiasis / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D004796:Clinical Enzyme Tests / Q000379:methods*; D004396:Coloring Agents; D005069:Evaluation Studies as Topic; D019694:Hepatitis B, Chronic / Q000097:blood; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011933:Reagent Kits, Diagnostic
chemical_list: D004396:Coloring Agents; D011933:Reagent Kits, Diagnostic; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D001663:Bilirubin