In my lectin haemaglutination assay by doing 2-fold serial dilution I have to add 50ul of trypsinized rabbit erythrocytes instead of normal rabbit erythrocytes and also I have heard that the wells need to be coated with EDTA. Can we do the EDTA coating ourselves? Please explain. Thank you. Also can we use direct human blood for the assay. If yes then how to store it till we do the assay?