Evaluation of an Electrochemiluminescent SARS-CoV-2 Antibody Assay

• Published in: The Journal of Applied Laboratory Medicine Vol. 5; no. 6; p. 1313
• Main Authors: Lau, C S, Hoo, S P, Yew, S F, Ong, S K, Lum, L T, Heng, P Y, Tan, J G, Wong, M S, Aw, T C
• Format: Journal Article Web Resource
• Language: English
• Published: England Oxford University Press 01.11.2020
• Subjects: Adult; Aged; Aged, 80 and over; Antibodies, Viral - blood; Antibodies, Viral - immunology; Betacoronavirus - genetics; Betacoronavirus - immunology; Betacoronavirus - isolation & purification; Clinical Laboratory Techniques - instrumentation; Clinical Laboratory Techniques - statistics & numerical data; Coronavirus Infections - blood; Coronavirus Infections - diagnosis; Coronavirus Infections - immunology; Coronavirus Infections - virology; COVID-19; COVID-19 Testing; Cross Reactions - immunology; Female; Fluoroimmunoassay - instrumentation; Fluoroimmunoassay - statistics & numerical data; Humans; Immunoglobulin G - blood; Immunoglobulin G - immunology; Luminescent Measurements - instrumentation; Luminescent Measurements - statistics & numerical data; Male; Middle Aged; Pandemics; Pneumonia, Viral - blood; Pneumonia, Viral - diagnosis; Pneumonia, Viral - immunology; Pneumonia, Viral - virology; Polymerase Chain Reaction - statistics & numerical data; Predictive Value of Tests; Reagent Kits, Diagnostic; RNA, Viral - isolation & purification; SARS-CoV-2; Seroconversion; Serologic Tests - instrumentation; Serologic Tests - statistics & numerical data; Time Factors; Young Adult
• ISSN: 2576-9456
• DOI: 10.1093/jalm/jfaa134

Little is known about the performance of the Roche novel severe acute respiratory syndrome coronavirus 2 antibody (anti-SARS-CoV-2) assay. We provide an extensive evaluation of this fully automated assay on Cobas e801/e602 immunoassay analyzers. We assessed the linearity, precision, and throughput of the Roche anti-SARS-CoV-2 assay. Sensitivity was calculated from 349 SARS-CoV-2 polymerase chain reaction (PCR) positive samples; specificity was determined from 715 coronavirus disease 2019 (COVID-19)-naive samples. We examined cross-reactivity against other antibody positive samples [syphilis, rheumatoid factor (RF), antinuclear antibody (ANA), double-stranded DNA (ds-DNA), influenza, dengue, hepatitis B (HBV), hepatitis C (HCV)] and the anti-SARS-CoV-2 kinetics. The assay cut-off index (COI) was linear up to 90.8. The interassay precision was 2.9% for a negative control (COI = 0.1) and 5.1% for a positive control (COI = 3.0). Assay time is 18 min and results are available 1 min later; throughput for 300 samples was 76 min. Only 1 case positive for HBsAg tested falsely positive; specificity was 99.9%. The assay has a sensitivity of 97.1% 14 days after PCR positivity (POS) and 100% at ≥21 days POS; 48.2% of cases had anti-SARS-CoV-2 within 6 days POS. In 11 patients in whom serum was available prior to a positive antibody signal (COI ≥1.0) the interval between the last negative and first positive COI (time to "seroconversion") on average is 3 days (range 1-6 days) and 4 more days (range 1-7) for the anti-SARS-CoV-2 to plateau. The Roche anti-SARS-CoV-2 assay shows excellent performance with minimal cross-reactivity from other viral and confounding antibodies. Antibody development and seroconversion appears quite early.