Comparative assessment of SARS-CoV-2 serology in healthcare workers with
Abbott Architect, Roche Elecsys and The Binding site ELISA immunoassays.
Abstract
Background: SARS-CoV-2 serology testing is key for assessing
seroprevalence and community transmission in both symptomatic and
asymptomatic contexts. Robust assay development requires assessment in
asymptomatic and non-hospitalised individuals to determine if
serological assays are sensitive to detect mild antibody-responses. Our
study evaluated the performance characteristics between two
high-throughput SARS-CoV-2 IgG nucleocapsid assays (Abbott and Roche)
and The binding site (TBS) Anti-Spike IgG/A/M ELISA kit in healthcare
workers. Methods: 252 samples were collected from Portsmouth Hospital
University NHS Trust (PHU) and The Dudley Group NHS Trust and analysed
for SARS-CoV-2 serology. We derived concordance, agreement and assay
performance as well as using receiver operating characteristic (ROC)
curves to redefine the assay threshold of the Abbott assay Results:
Result concordance between the Abbott and TBS was 66%. Discrepant
samples were analysed using the Roche assay which showed 100% agreement
with the TBS assay. In samples analysed >58 days post-PCR,
the sensitivity of Abbott and Roche was 100%. In samples analysed
>100 days post-PCR the sensitivity of the Abbott assay
dropped to 77.2% but remained at 100% for the Roche assay. A redefined
Abbott threshold of 0.64 increased the sensitivity to 90% giving
results similar to the Roche and TBS assays. Conclusion: This study
demonstrated use of manufacturer cut-off threshold for Abbott SARS-CoV-2
IgG immunoassay induced lower sensitivity and higher false negative
outcomes in comparison to TBS and Roche. Our findings established TBS
can be implemented as a viable alternative for SARS-CoV-2 serology
testing where high-throughput assays are not available on site.