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

Maritz, Leo; Woudberg, Nicholas J; Bennett, Amber C; Soares, Andreia; Lapierre, Florian; Devine, Justin; Kimberg, Matti; Bouic, Patrick J

Aim: 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. Results: The assay demonstrated high levels of diagnostic specificity and sensitivity (85–99% for all analytes). Serum IgG, IgM, IgA and nAb correlated positively (R(2) = 0.937, R(2) = 0.839, R(2) = 0.939 and R(2) = 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). In vitro SARS-CoV-2 pseudotype neutralization correlated positively with the solid phase nAb signals in convalescent donors (R(2) = 0.458, p < 0.05). Conclusion: The assay is applicable in efficacy studies, infection monitoring and postmarketing surveillance following vaccine rollout.