Clinical evaluation of SARS-CoV-2 point-of-care antibody tests

Abstract

The aim of this study was to assess the analytic and clinical performance of four rapid lateral flow point-of-care tests (POCTs) for identifying SARS-CoV-2-specific antibodies. A retrospective study was conducted between 22 January and 30 March 2020 on 132 serum samples for SARS-CoV-2-specific antibody detection referred to a tertiary referral hospital laboratory in New South Wales. Multiple sera were tested from 20 confirmed or suspected COVID-19 patients with SARS-CoV-2-specific antibodies detected by immunofluorescence (IFA) or neutralisation, and 71 SARS-CoV-2 uninfected individuals. We measured the sensitivity and specificity for detection of SARS-CoV-2 IgM and IgG antibodies for each POCT in comparison to positive SARS-CoV-2-specific IFA and viral neutralisation, our current laboratory benchmark tests. All POCTs were found to have a low analytic sensitivity for SARS-CoV-2 antibodies, ranging from 27.3% to 58.2%, with a specificity between 88.3% and 100%, and a low clinical sensitivity from 45% to 65%, with a clinical specificity between 87.3% and 100%. All POCTs had an increased sensitivity when specimens were collected more than 14 days from onset of symptoms. The detection using point-of-care testing of SARS-CoV-2-specific antibodies after disease onset lagged behind IFA by a range of 0-9 days. POCTs promise the benefit of providing quick easy testing for SARS-CoV-2-specific antibodies. However, their poor sensitivity and delayed antibody detection make them unsuitable as a diagnostic or screening tool alone.

Keywords: COVID-19; SARS-CoV-2; point-of-care testing; serology.