SARS-COV-2 immunoassay evaluation: results
FIND is conducting independent evaluations to assess the performance of selected antibody (Ab) immunoassays (RDTs and manual ELISAs) and antigen (Ag) RDTs.
1. Antibody (Ab) tests: Each lateral flow format index test is being evaluated using archived, frozen serum/plasma at more than one site, whereas each manual ELISA is being evaluated by at least one site, some at two. We are presenting site-specific data and combined data across sites: each site tested at least 100 positive samples and 150 negative samples.
2. Antigen (Ag) tests: We are conducting prospective diagnostic evaluation studies across multiple, independent sites to determine the accuracy of COVID-19 antigen RDTs. The index tests include novel lateral flow format tests that detect recombinant SARS-CoV-2 antigens. Interim analyses are performed at 25% and 50% enrolment and the evaluation is stopped if tests do not meet 95% specificity.
More details can be found in the Overview of FIND methodology for immunoassay evaluations.
Here we summarize the interim results for the evaluation of the first 4 Ab RDTs from one site. More product-specific performance point-estimates will be posted as data become available.
Table 1: Point estimates (95% confidence interval) for sensitivity, stratified according to days from symptom onset, and for overall specificity according to antibody isotype (IgM, IgG or IgM+IgG in combination) for four antibody RDTs evaluated at one site.