The Spike glycoprotein exists as a trimer located on the outside of the viral membrane. Within the S are two main subunits: S1 and S2. We have recombinantly produced the S1 subunit, attached to a 6 X Histidine Tag. The predicted molecular weight of this protein is 76kDa, however due to the extensive glycosylation it is observed to run at 120kDa. This antigen is available in 100ug research amounts, as well as mg amounts. Our S1-His has been externally validated, appearing in a UCT publication showing it is recognised by SARS-CoV-2 positive patient serum. It is also on an antibody test kit that has been SAHPRA approved and shown to have specificity of 100% and Sensitivity for IgM of 94% and IgG of 100%.