Validation of high-throughput, semiquantitative solid-phase SARS coronavirus-2 serology assays in serum and dried blood spot matrices.

Serological assays for the detection of anti-SARS coronavirus-2 (SARS-CoV-2) antibodies are essential to the response to the global pandemic. A ligand binding-based serological assay was validated for the semiquantitative detection of IgG, IgM, IgA and neutralizing antibodies (nAb) against SARS-CoV-2 in serum. The assay demonstrated high levels of diagnostic specificity and sensitivity (85-99% for all analytes). Serum IgG, IgM, IgA and nAb correlated positively (R = 0.937, R = 0.839, R = 0.939 and R = 0.501, p < 0.001, respectively) with those measured in dried blood spot samples collected using the hemaPEN microsampling device (Trajan Scientific and Medical, Victoria, Australia). SARS-CoV-2 pseudotype neutralization correlated positively with the solid phase nAb signals in convalescent donors (R = 0.458, p < 0.05). The assay is applicable in efficacy studies, infection monitoring and postmarketing surveillance following vaccine rollout.