New procedure for detecting antinuclear antibodies using glucose oxidase immunoenzyme technic.

Enzyme glucose oxidase was used as the label on the secondary antibody in an indirect ANA-test procedure using rat kidney tissue as the antigen-source. Glucose oxidase is not endogenously present in mammalian tissues and, therefore, produces no background staining as obtained with flurochrome and peroxidase labels, which are commonly used to detect tissue antigens. Pseudoperoxidase-like activity of the haptoglobin-hemoglobin complexes in mammalian tissues is responsible for the interfering background stain when peroxidase label is used. Unlike Diaminobenzidine, the staining reagent commonly used with peroxidase, chromogenic reagents used with glucose oxidase are not carcinogenic. Glucose oxidase as a label for antibodies has advantages over flurochrome labels in being permanently stable, producing no background stain, and increasing the sensitivity of the method. Comparative evaluation of the glucose oxidase procedure and the commonly used flurochrome-ANA and peroxidase-ANA methods is reported. Results with 150 serum samples show the potential of this new method as a routine ANA-testing procedure in clinical laboratories.