Evaluation of Three Commercial SARS-CoV-2 Serologic Assays and Their Performance in Two-Test Algorithms

• Published in: Journal of clinical microbiology 2020-12, Vol.59 (1)
• Main Authors: Turbett, Sarah E, Anahtar, Melis, Dighe, Anand S, Garcia Beltran, Wilfredo, Miller, Tyler, Scott, Hannah, Durbin, Sienna Marie, Bharadwaj, Maheetha, Thomas, Jason, Gogakos, Tasos S, Astudillo, Michael, Lennerz, Jochen, Rosenberg, Eric S, Branda, John A
• Format: Article
• Language: English
• Subjects: Algorithms; Antibodies, Viral - blood; Clinical Laboratory Techniques - methods; Coronavirus Nucleocapsid Proteins - immunology; COVID-19; COVID-19 - diagnosis; COVID-19 Serological Testing - methods; Humans; SARS-CoV-2; Sensitivity and Specificity; Spike Glycoprotein, Coronavirus - immunology; Virology
• ISSN: 0095-1137; 1098-660X; 1098-660X
• DOI: 10.1128/JCM.01892-20

Sensitive and specific severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic assays are needed to inform diagnostic, therapeutic, and public health decision-making. We evaluated three commercial serologic assays as stand-alone tests and as components of two-test algorithms. Two nucleocapsid antibody tests (Abbott IgG and Roche total antibody) and one spike protein antibody test (DiaSorin IgG) were included. We assessed sensitivity using 128 serum samples from symptomatic PCR-confirmed coronavirus disease 2019 (COVID-19)-infected patients and specificity using 1,204 samples submitted for routine serology prior to COVID-19's emergence, plus 64 pandemic-era samples from SARS-CoV-2 PCR-negative patients with respiratory symptoms. Assays were evaluated as stand-alone tests and as components of a two-test algorithm in which positive results obtained using one assay were verified using a second assay. The two nucleocapsid antibody tests were more sensitive than the spike protein antibody test overall (70% and 70% versus 57%;  ≤ 0.003), with pronounced differences observed using samples collected 7 to 14 days after symptom onset. All three assays were comparably sensitive (≥89%;  ≥ 0.13) using samples collected >14 days after symptom onset. Specificity was higher using the nucleocapsid antibody tests (99.3% and 99.7%) than using the spike protein antibody test (97.8%;  ≤ 0.002). When any two assays were paired in a two-test algorithm, the specificity was 99.9% (