At the outset of the COVID-19 pandemic, few diagnostic tests were available to identify infection and direct patient management. To help develop an appropriate diagnostic test, GH Labs and our research partners first set out to create high-performing antibody pairs by obtaining and then screening all available COVID antibodies using our high-throughput custom robotic platform in a lateral-flow assay (LFA). Within two months of testing 90 antibodies, the team had created antibody pairings for the two main antigen targets (nucleocapsid and spike proteins) in SARS-CoV-2. Each of the pairings was then evaluated for specificity and signal strength in the context of LFA. In total, 9 rounds covering 1954 antibody pairs were screened in 17,932 LFA tests.
The nucleocapsid target produced superior results with a higher abundance in virus (50X spike), and several attractive candidates were identified and further characterized with clinical samples. Shortly thereafter, we disseminated our results in four open access publications to support the development of several commercially available COVID antigen tests, including by one of our partners, Clip Health, who integrated our results and selection of antibodies to accelerate the development of their high-performance luminescent signal LFA format (readable by cell phone).
The resulting product, Clip COVID Rapid Antigen Test, received Emergency Use Authorization on Dec 7, 2020, with a performance of 97% sensitivity and 100% specificity. Since receiving EUA, many hundreds of thousands of test units have been procured and distributed to CLIA-waived labs around the United States.