血凝试验( Hemagg! urination Assay) t buffer virus dilution RBc(approx 105) + virus o o。°。+ buffer 1:2048 1:4096 Hemagglutination assay血凝试验（Hemagglutination Assay） + virus + buffer + RBC (approx. 105 ) + buffer + virus dilution 1:4 1:2048 Hemagglutination assay … … … 1:4096