AUTHOR=O'Kelly Brendan , McLaughlin Ronan , O'Doherty Roseann , Carroll Hailey , Murray Roisin , Dilworth Rachel , Corkery Laura , Cotter Aoife G. , McGinty Tara , Muldoon Eavan G. , Cullen Walter , Avramovic Gordana , Sheehan Gerard , Sadlier Denise , Higgins Michaela , O'Gorman Peter , Doran Peter , Inzitari Rosanna , Holden Sinead , O'Meara Yvonne , Ennis Sean , Lambert John S. 

TITLE=Rapid and Laboratory SARS-CoV-2 Antibody Testing in High-Risk Hospital Associated Cohorts of Unknown COVID-19 Exposure, a Validation and Epidemiological Study After the First Wave of the Pandemic

JOURNAL=Frontiers in Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.642318

DOI=10.3389/fmed.2021.642318

ISSN=2296-858X

ABSTRACT=<p><bold>Objective:</bold> We aimed to use SARS-CoV-2 antibody tests to assess the asymptomatic seroprevalence of individuals in high-risk hospital cohorts who's previous COVID-19 exposure is unknown; staff, and patients requiring haemodialysis or chemotherapy after the first wave.</p><p><bold>Methods:</bold> In a single Center, study participants had five SARS-CoV-2 antibody tests done simultaneously; one rapid diagnostic test (RDT) (Superbio Colloidal Gold IgM/IgG), and four laboratory tests (Roche Elecsys® Anti-SARS-CoV-2 IgG [RE], Abbott Architect i2000SR IgG [AAr], Abbott Alinity IgG [AAl], and Abbott Architect IgM CMIA). To determine seroprevalence, only positive test results on laboratory assay were considered true positives.</p><p><bold>Results:</bold> There were 157 participants, of whom 103 (65.6%) were female with a median age of 50 years (range 19–90). The IgG component of the RDT showed a high number of false positives (<italic>n</italic> = 18), was inferior to the laboratory assays (<italic>p</italic> &lt; 0.001 RDT vs. AAl/AAr, <italic>p</italic> &lt; 0.001 RDT vs. RE), and had reduced specificity (85.5% vs. AAl/AAr, 87.2% vs. RE). Sero-concordance was 97.5% between IgG laboratory assays (RE vs. AAl/AAr). Specificity of the IgM component of the RDT compared to Abbott IgM CMIA was 95.4%. Ten participants had positivity in at least one laboratory assay, seven (9.9%) of which were seen in HCWs. Two (4.1%) hematology/oncology (H/O) patients and a single (2.7%) haemodialysis (HD) were asymptomatically seropositive. Asymptomatic seroprevalence of HCWs compared to patients was not significant (<italic>p</italic> = 0.105).</p><p><bold>Conclusion:</bold> HCWs (9.9%) had higher, although non-significant asymptomatic seroprevalence of SARS-CoV-2 antibodies compared to high-risk patients (H/O 4.1%, HD 2.7%). An IgM/IgG rapid diagnostic test was inferior to laboratory assays. Sero-concordance of 97.5% was found between IgG laboratory assays, RE vs. AAl/AAr.</p>