Evaluation of three commercial and two non-commercial immunoassays for the detection of prior infection to SARS-CoV-2

J Appl Lab Med. 2021 Jul 1;jfab072. doi: 10.1093/jalm/jfab072. Online ahead of print.


Background: Serological testing provides a record of prior infection with SARS-CoV-2, but assay performance requires independent assessment.

Methods: We evaluated three commercial (Roche Diagnostics pan-IG, Epitope Diagnostics IgM and IgG) and two non-commercial (Simoa, Ragon/MGH IgG) immunoassays against 1083 unique samples that included 251 PCR positive and 832 pre-pandemic samples.

Results: The Roche assay registered the highest specificity 99.6% (3/832 false positives), the Ragon/MGH assay 99.5% (4/832), the primary Simoa assay model 99.0% (8/832), and the Epitope IgG and IgM 99.0 (8/830) and 99.5% (4/830) respectively. Overall sensitivities for the Simoa, Roche pan-IG, Epitope IgG, Ragon/MGH IgG, and Epitope IgM were 92.0%, 82.9%, 82.5%, 64.5% and 47.0% respectively. The Simoa immunoassay demonstrated the highest sensitivity among samples stratified by days post symptom onset (PSO), < 8 days PSO (57.69%) 8-14 days PSO (93.51%), 15-21 days PSO (100%), and > 21 days PSO (95.18%).

Conclusions: All assays demonstrated high to very high specificities while sensitivities were variable across assays.

Keywords: COVID-19; SARs-CoV-2; antibodies; immunoassays; performance; sensitivity; serology; specificity.