The V-PLEX SARS-CoV-2 Panel 28 (Mouse IgM) Kit is a qualitative multiplex serology assay for mouse antibodies to ten RBD antigens from variants of SARS-CoV-2. It includes antigens from Alpha, Beta, Delta, and several sublineages of Omicron, including BA.2, BA.2.12.1, BA.3, BA.4, BA.5, and two BA.2 RBD antigens with extra mutations predicted to further evade neutralization. Panel 28 includes: A (WT), (B.1.1.7), (B.1.351; B.1.351), (AY.3; AY.4; AY.4.2; AY.5; AY.6; AY.7; AY.12; AY.14; B.1.617.2; B.1.617.2+ΔY144), (BA.2; BA.2.1; BA.2.2; BA.2.3; BA.2.5; BA.2.6; BA.2.7; BA.2.8; BA.2.10; BA.2.10.1; BA.2.12), (BA.2.12.1), (BA.2+L452M), (BA.2+L452R), (BA.3), and (BA.4; BA.5).