Antibody testing for COVID-19: A report from the National COVID Scientific Advisory Panel



Adams, Emily, Ainsworth, Mark, Anand, Rekha, Andersson, Monique, Auckland, Kathryn, Baillie, Kenneth, Barnes, Eleanor ORCID: 0000-0002-0860-0831, Beer, Sally, Bell, John, Berry, Tamsin
et al (show 61 more authors) (2020) Antibody testing for COVID-19: A report from the National COVID Scientific Advisory Panel.

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Abstract

ABSTRACT Objectives: The COVID-19 pandemic caused >1 million infections during January-March 2020. There is an urgent need for reliable antibody detection approaches to support diagnosis, vaccine development, safe release of individuals from quarantine, and population lock-down exit strategies. We set out to evaluate the performance of ELISA and lateral flow immunoassay (LFIA) devices. Design: We tested plasma for COVID (SARS-CoV-2) IgM and IgG antibodies by ELISA and using nine different LFIA devices. Setting: We performed laboratory work at the University of Oxford. Participants: We used a panel of plasma samples from individuals who have had confirmed COVID infection based on a PCR result (n=40), and pre-pandemic negative control samples banked in the UK prior to December-2019 (n=142). Main outcome measures: We recorded optical density results from ELISA experiments and positive/negative/invalid results from LFIA devices. Results: ELISA detected IgM or IgG in 34/40 individuals with a confirmed history of COVID infection (sensitivity 85%, 95%CI 70-94%), vs. 0/50 pre-pandemic controls (specificity 100% [95%CI 93-100%]). IgG levels were detected in 31/31 COVID-positive individuals tested ≥10 days after symptom onset (sensitivity 100%, 95%CI 89-100%). IgG titres rose during the 3 weeks post symptom onset and began to fall by 8 weeks, but remained above the detection threshold. Point estimates for the sensitivity of LFIA devices ranged from 55-70% versus RT-PCR and 65-85% versus ELISA, with specificity 95-100% and 93-100% respectively. Within the limits of the study size, the performance of most LFIA devices was similar. Conclusions: Currently available commercial LFIA devices do not perform sufficiently well for individual patient applications. ELISA can be calibrated to be specific for detecting and quantifying SARS-CoV-2 IgM and IgG and is highly sensitive for IgG from 10 days following first symptoms.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 23 Jun 2020 10:04
Last Modified: 05 Nov 2020 06:10
DOI: 10.1101/2020.04.15.20066407
Open Access URL: https://doi.org/10.1101/2020.04.15.20066407
URI: http://livrepository.liverpool.ac.uk/id/eprint/3090727