Assay Harmonization and Use of Biological Standards To Improve the Reproducibility of the Hemagglutination Inhibition Assay: a FLUCOP Collaborative Study
Joanna Waldock, Lingyi Zheng, Edmond J. Remarque, Alexandre Civet, Branda Hu, Sarah Lartey Jalloh, Rebecca Jane Cox, Sammy Ho, Katja Höschler, Thierry Ollinger, Claudia Maria Trombetta, Othmar G. Engelhardt, Catherine Caillet
Abstract
The hemagglutination inhibition (HAI) assay is the most commonly used serology assay to detect antibodies from influenza vaccination or influenza virus infection. This assay has been used for decades but requires improved standardization of procedures to provide meaningful data. We designed a large study to assess selected parameters for their contribution to assay variability and developed a standard protocol to promote consistent HAI testing methods across laboratories. The use of this protocol and common reagents resulted in lower levels of variability in results between participating laboratories than achieved using in-house HAI testing. Human sera sourced from vaccination campaigns over several years, and thus including antibody to different influenza vaccine strains, served as effective assay standards. Based on our findings, we recommend the use of a common protocol and/or human serum standards, if available, for testing human sera for the presence of antibodies against seasonal influenza using turkey red blood cells.