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. 2022 May 26:6:358.
doi: 10.12688/wellcomeopenres.17231.2. eCollection 2021.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody lateral flow assay for antibody prevalence studies following vaccination: a diagnostic accuracy study

Alexandra Cann #  1   2 , Candice Clarke #  3   4 , Jonathan Brown #  1 , Tina Thomson  3   4 , Maria Prendecki  3   4 , Maya Moshe  3   4 , Anjna Badhan  1 , Bryony Simmons  5 , Bob Klaber  2 , Paul Elliott  1   2   6   7 , Ara Darzi  1   2   8 , Steven Riley  1   7 , Deborah Ashby  1   6 , Paul Martin  3 , Sarah Gleeson  3 , Michelle Willicombe  3   4 , Peter Kelleher  1   9 , Helen Ward  1   2   6   7   8 , Wendy S Barclay  1 , Graham S Cooke  1   2   8
Affiliations

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody lateral flow assay for antibody prevalence studies following vaccination: a diagnostic accuracy study

Alexandra Cann et al. Wellcome Open Res. .

Abstract

Background: Lateral flow immunoassays (LFIAs) are able to achieve affordable, large scale antibody testing and provide rapid results without the support of central laboratories. As part of the development of the REACT programme extensive evaluation of LFIA performance was undertaken with individuals following natural infection. Here we assess the performance of the selected LFIA to detect antibody responses in individuals who have received at least one dose of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. Methods: This was a prospective diagnostic accuracy study. Sampling was carried out at renal outpatient clinic and healthcare worker testing sites at Imperial College London NHS Trust. Two cohorts of patients were recruited; the first was a cohort of 108 renal transplant patients attending clinic following two doses of SARS-CoV-2 vaccine, the second cohort comprised 40 healthcare workers attending for first SARS-CoV-2 vaccination and subsequent follow up. During the participants visit, finger-prick blood samples were analysed on LFIA device, while paired venous sampling was sent for serological assessment of antibodies to the spike protein (anti-S) antibodies. Anti-S IgG was detected using the Abbott Architect SARS-CoV-2 IgG Quant II CMIA. A total of 186 paired samples were collected. The accuracy of Fortress LFIA in detecting IgG antibodies to SARS-CoV-2 compared to anti-spike protein detection on Abbott Assay Results: The LFIA had an estimated sensitivity of 92.0% (114/124; 95% confidence interval [CI] 85.7% to 96.1%) and specificity of 93.6% (58/62; 95% CI 84.3% to 98.2%) using the Abbott assay as reference standard (using the threshold for positivity of 7.10 BAU/ml) Conclusions: Fortress LFIA performs well in the detection of antibody responses for intended purpose of population level surveillance but does not meet criteria for individual testing.

Keywords: Antibodies; Covid-19; LFIA; Lateral flow; Neutralisation; SARS-CoV-2; Seroprevalence.

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Conflict of interest statement

No competing interests were disclosed.

Figures

Figure 1.
Figure 1.. Paired Quantitative anti-S titres (Abbott) between those testing positive and negative on Fortress lateral flow immuno-assay (LFIA) for combined cohorts 1 and 2.
(Y-axis uses Log 2 scale, data points below the lower limit of detection are assigned arbitrary value of 0.01 for plotting).
Figure 2.
Figure 2.. Flowchart detailing testing results for Cohort 1 and Cohort 2 and Combined Cohort.
LFIA=Fortress lateral flow immuno-assay.
Figure 3.
Figure 3.
( A) Distribution of NT50 (neutralisation titre) values for individuals within cohort 2 according to whether positive or negative by Fortress lateral flow immuno-assay (LFIA) (Y-axis uses Log 10 scale, data points below the lower limit of detection are assigned arbitrary value of 0.01 for plotting) ( B) Relationship between neutralisation titre and anti-S titre in Abbott assay (green representing those LFIA positive, red LFIA negative). (Y-axis uses Log 2 scale, data points below the lower limit of detection are assigned arbitrary value of 0.01 for plotting). SARS-CoV-2 NT=severe acute respiratory syndrome coronavirus 2 neutralisation titre.
See this image and copyright information in PMC

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