The predictive value of serological testing during the COVID-19 pandemic
updated: 4 June 2020 original published date: 30 April 2020
This rapid research brief synthesises the evidence on the predictive value of serological antibody tests and the comparability of point-of-care (POC) tests to laboratory tests.
- Point-of-care (POC) and laboratory-based serological tests can be used to detect antibodies against SARS-CoV-2. Globally, health authorities are evaluating their use to determine individual immunity, the prevalence of infection in the population, to aid in diagnosis, to aid in contact tracing, and to inform when restrictions can be eased.
- Laboratory-based tests are both quantitative and qualitative. POC tests deliver only a positive or negative result; or a semi-quantitative result at best.
- Neither type of serological test is currently ready for widespread deployment. However rapid advances can be expected.
- With respect to immunity, the interpretation of serological antibody tests relies on a clear understanding of the immune response to SARS-CoV-2, which currently remains undefined.
- For as long as the prevalence of COVID-19 is low in Australia and available serological tests are not approaching 100% specificity, serological testing to measure the prevalence of COVID-19 will not be meaningful. However, if highly accurate serological techniques operating in some academic labs are validated against national standards, they could offer a means for predicting prevalence at the population level.
- Laboratory-based serological testing is being used to identify donors of convalescent plasma that could be used to treat critically ill COVID-19 patients.