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CLINICAL CHEMISTRY 1 Glucose Oxidase RATIONALE Glucose is the end product of carbohydrate metabolism. This is mainly used by humans as the source of carbon and energy through glycolysis and Kreb cycle. The blood glucose level is regulated by the actions of various hormones. In general, however, insulin is the major hormone that regulates blood concentration. It is produced from the beta cell of the Islets of Langerhans. Insulin decreases the blood glucose level by promoting glucose uptake by the cell. Various methods are available for the determination of blood glucose level. Today, there are POCT that are available and basically, this follows the Glucose oxidase principle. MATERIALS/REAGENTS Serum specimen Glucose reagent kits % % % Serologic pipet ‘S Automatic micropipette % Test tubes REACTION PRINCIPLE Glucose + O; + H;Q = ---- GOD-----> __ glucoronic acid + H:0; 2H,0, + 4-aminophenazone + pheol ----- POD--- > quinoneimine + 4H;0 The glucose is determined after enzymatic oxidation in the presence of glucose oxidase. The formed hydrogen peroxide reacts under catalysis of peroxide with phenol and 4-aminophenazone to a red-velvet quioneimine dye as indicator, MACRO SEMI MICRO Pipette Standard Reagent Standard Reagent into or blank or blank cuvettes | Sample Sample Standard | 20uL 0 ---------- VWOuL — ---------- or Sample Reagent | 2000uL 2000uL 1000uL 1000uL Mix, incubate for 10 min at 20-25°C or 5 min at 37°C. Measure the absorbance of STD and the sample against the reagent blank within 60min. (AA) Calculation _ Asample C= 100x ASTD [mg/dl] _ Asample C=5.55x ASTD [mmol/L] NORMAL VALUES Serum and Plasma (Fasting): 75-115 mg/dL or 4.2 -6.4 mmol/L CLINICAL SIGNIFICANCE TYPE 1 DIABETES Results from Beta cell destruction, usually leading to absolute insulin deficiency TYPE 2 DIABETES Results from progressive insulin secretory defect on the background of insulin resistance GESTATIONAL DIABETES | Diagnosed during MELLITUS (GDM) pregnancy OTHER SPECIFIC TYPES Due to other causes (eg. Genetic defects in beta- cell function, genetic defects in insulin action, diseases of the exocrine pancreas, such as cystic fibrosis, and drug or chemical induced such as treatment of aids or after-organ transplantation) 
