Evaluation of Immunoassay Interference Reduction Technologies

Problems with non‐specific binding and assay interferences can cause high background and loss of sensitivity in many IVD applications including ELISA, western blotting and microarrays. Interference issues can arise due to inadequate blocking of a membrane and ELISA plates, or inferior surface chemistries, or heterophilic antibodies such as; HAMA and RF. Here we examine interference reduction technologies versus in‐house and commercial products across multiple IVD applications. Interference reduction technologies were evaluated for four common assay formats: 1. Non‐specific binding was reduced in a functional ELISA using both protein containing and protein‐free blocker formulations developed for dried stability applications. These novel formulations were also able to stabilize the structure/function of the antibody in the dried state, leading to an increase in shelf life of immunoassay plates over common in‐house formulations. 2. In a traditional membrane immunoassay, western blotting results indicated a decrease in background with a set of new blocker formulations compared to common in‐house buffers. Sensitivity for the novel formulations was shown to be superior allowing for improved signal‐to‐noise for membrane immunoassay's. 3. In a standard microarray format, comparison of a novel surface chemistry coating to commercially available epoxysilane surfaces, showed less background in a protein array format. The superior slides display more distinct spots with consistently low background across the slide. 4. Finally, matrix interference and false positive/negative results caused by heterophilic antibodies were reduced by 43% compared to negative controls using a synthetic assay diluent. Solutions discussed here provide the tools necessary to develop and optimize immunoassays that are sensitive, reproducible, and robust while demonstrating the ability to reduce assay interference across multiple IVD applications.