Screening Method for Glucose of Rlood Serum Utilizing Glucose Oxidase and an Indophenol Indicator, by Leonard A. Dobrick with the Technical Assistance of Herbert

Approximately 80,000 blood specimens are submitted to this bureau annually for syphilis serology testing, and it was proposed’ that these specimens be further employed for purposes of diabetic screening. To carry out this type of program, it was desirable to devise a rapid method for the mass determination of glucose levels in blood serum. This paper describes such a method. It is well known that established methods which require a protein-free filtrate are generally unsuited for the estimation of blood glucose on a large scale. Wilkerson and Heftmann (l), however, have devised a screening method which, with the aid of special apparatus, has been successfully applied to the routine examination of large numbers of specimens. In recent years, the enzyme, glucose oxidase, has been employed toward a more accurate appraisal of glucose in biological fluids (2). Through the manometric measurement of oxygen uptake, Keilin and Hartree (3) have demonstrated that the oxidation of glucose proceeds specifically and quantitatively in the presence of this enzyme. The hydrogen peroxide liberated in the reaction has been utilized by a recently marketed paper tape to yield a chromogenic oxidation product, the color intensity of which is semiquantitatively proportional to glucose concentrations in urine and blood plasma (4). The method described herein is based upon our independent finding that the oxidation-reduction indicator, 2,6-dichlorobenzenone-indophenol, can replace molecular oxygen as the hydrogen acceptor in the glucose-glucose oxidase reaction. The literature discloses, however, that this finding in fact had only confirmed earlier observations (5). In demonstrating that under anaerobic conditions a quantitative as well as a qualitative relationship exists between glucose oxidized and indophenol reduced, a new method is evolved which is particularly applicable to the mass screening of glucose levels in blood sera.