Nature of Materials in Serum That Interfere in the Glucose Oxidase—Peroxidase—o-Dianisidine Method for Glucose, and Their Mode of Action

Abstract

Abstract Separation of blood serum on Sephadex G-100 reveals three fractions that interfere with the glucose oxidase— peroxidase method for serum glucose when o-dianisidine is used as the chromogen. A low-molecular-weight fraction containing primarily uric acid, a fraction containing protein with a molecular weight of about 40 000, and a fraction of even higher molecular weight (∼ 500 000) each interfered with glucose recovery when glucose was measured by this procedure. The uric acid fraction and the isolated 40 000 molecular weight fraction interfere by competing with o-dianisidine for hydrogen peroxide in the peroxidase-catalyzed color-formation step. The high-molecular-weight fraction not only interferes with the peroxidase reaction, but also with the glucose oxidase reaction itself. These agents cause values to be low by as much as 20% in the manual determination of glucose in normal serum if their interference is not recognized.