EXPRESS: Comparison of four high throughput, automated immunoassays for the detection of SARS-CoV-2 antibodies.

Oakey, Jane; Haslam, Shonagh; Brown, Andrew Peter; Eglin, Janet; Houghton, Brittany; Singleton, Dawn

BACKGROUND A number of immunoassays have been developed to measure antibodies specific to SARS-CoV-2. More data is required on their comparability, particularly amongst those with milder infections and in the general practice population. The aim of this study was to compare four high throughput automated anti SARS-CoV-2 assays using samples collected from hospitalised patients and healthcare workers with confirmed SARS-CoV-2 infection. In addition, we collected general practice samples to compare antibody results and determine seroprevalence. METHODS Samples were collected from 57 hospitalised patients and 9 healthcare workers at 14 days and at 28 days following confirmed SARS-CoV-2 infection. Samples were also collected from 225 patients presenting to general practice. Four assays were used: Abbott Architect IgG, Beckman Coulter DxI 800 IgG, Roche Cobas e801 total antibody and Siemens Advia Centaur XPT total antibody. RESULTS All 4 assays showed concordance at 14 days in 83.9% of hospitalised patients and in 66.7% of healthcare workers. All 4 assays showed concordance at 28 days in 88.4% of hospitalised patients and 77.8% of healthcare workers. The sensitivity to detect recent infection was higher for the IgG assays than the total assays. All 4 assays showed concordance of 95.1% in the general practice population. Seroprevalence ranged from 4.9-5.8% depending on the assay used. CONCLUSIONS All 4 assays showed excellent comparability but it may be possible to obtain a negative result for any of the anti SARS-CoV-2 assays in patients with confirmed previous SARS-CoV-2 infection. An equivocal range would be useful for all anti SARS-CoV-2 assays.