A2_7 Qualitative Immunoassay

As immunoassays have evolved to meet specific clinical needs, qualitative tests that give a yes/no answer have become common. Blood screening tests are often of this type; pregnancy tests are the most well-known example. The simplicity of the technique from the user’s perspective belies that this is an immunoassay format that requires extra sophistication, because the test provides clinical interpretation, and not merely the analyte concentration.

This chapter describes the principle features of qualitative and semi-quantitative immunoassays. Performance characteristics and other regulatory requirements related to clinical application of qualitative immunoassays are explained. The assay design, optimization, calibration, validation and verification steps are described.

Jianwen He (M.D. & Ph.D.) is currently the R&D Sr. Manager for BioMerieux Shanghai Biotech with responsibility for managing rapid testing and other immunoassay development. Prior to joining BioMerieux, Jianwen worked as a staff scientist and R&D manager for assay development in the Immunoassay Diagnostics Center of Beckman Coulter, Inc for 10 years, where he helped design and develop many CLIA assays including Access Inhibin A. Jianwen also worked as North Asia commercial manager for DiaSorin S.p.A. for a couple of years, where he managed the RIA, ELISA, and CLIA immunoassay business for a matured market. Jianwen has gone through immunoassay from discovery, research and development to commercialization. Jianwen has a Ph.D. in molecular virology.

Simon Parker studied Microbiology at Sheffield University, has a Virology Fellowship from the Institute of Biomedical Sciences and a Ph.D in Medicine from University College London. Simon currently works as the Serology Development Manager for Roche Diagnostics Limited in the UK. Prior to joining Roche, Simon was an R&D group leader for DiaSorin and Abbott Diagnostics for several years in commercial immunoassay development from first concept to manufacture. Previously Simon worked in the public sector, developing both serological and molecular tools for the diagnosis and epidemiological study of human and veterinary pathogens.

Qualitative immunoassay, semiquantitative immunoassay, cutoff value, indeterminate, gray zone, initially reactive, repeatedly reactive, confirmed positive, indirect immunoassay, immunocapture immunoassay, sandwich immunoassay, rheumatoid factor, receiver operating characteristics curve, calibration, viral antibody test, avidity, verification, validation.