Antibody Testing for CoVID-19

Frank Bell, MD
Pediatric Infectious Disease
Swedish Medical Center, Seattle

Given the enormous challenges we face with CoVID-19 and the limited scope and availability of PCR assays, antibody testing for SARS-CoV-2 has been widely anticipated. News that serologic testing is now available and about to be rolled-out is to be welcomed, but uncertainties remain about who should be tested and about how the results of testing should be used.

A large number of antibody-testing systems have been developed by a myriad of suppliers, for the most part circumventing standard processes of FDA review and approval. Suggested areas for use of these serologic tests have included help with CoVID diagnosis in acute disease, screening of blood from patients who have recovered from CoVID for use in hyperimmune serum therapy, epidemiologic surveillance to assess the scale of the epidemic, and in the hope to assess a patient or employee’s immunity from future disease from SARS-CoV-2.

There are uncertainties around the accuracy of available test systems and substantial challenges in interpreting the results of testing, particularly as they apply to individual patients. As data is collected from healthcare workers, other exposed individuals and the wider community we may be able to begin to address some of these uncertainties, but many will likely remain. Of greatest concern is the possibility that a ‘false-positive’ result (perhaps, for example, reflecting cross-reacting antibody from previous ‘non-CoVID-19’ coronavirus infections) will lead to personal behaviors (e.g. a relaxation of distancing and hygiene precautions) or deployments that may increase rather than decrease future health risks for tested individuals.

Carefully-conducted community-based surveys involving serological testing for SARS-CoV-2 promise better understanding of the true scale of this pandemic and may inform decisions to allow us to ‘open back up’ again. The implications of antibody test-results for individual patients and frontline staff are much less clear. Careful discussion around the risks and benefits of testing will be important before a rush to embrace exciting but still untested technology.