The Five health care employees were definitively seronegative versus H5 in all assays, which suggests they weren't contaminated with H5. Hemagglutinin inhibition (Hello) assay: The HI assay assessments for antibodies into the hemagglutinin of the precise influenza virus using red blood cells (RBC). Various sorts of RBCs have been assessed https://www.dailypioneer.com/2020/sunday-edition/building-sustainable-global-institutions.html