ABSTRACT
We used the dried tube specimen (DTS) procedure to develop the COVID-19 Serology Control Panel (CSCP). The CSCP contains five well-characterized SARS-CoV-2 pooled plasma samples made available for labs around the world to compare test kits, use for external quality assurance, harmonize laboratory testing, and train laboratory workers. Article Summary LineThe dried tube specimen system is a highly effective and resilient way to provide laboratories with well-characterized serology materials. The CSCP can help clinical laboratories inform their choice of diagnostic test to supplement clinical diagnoses of SARS-CoV-2 infection.
ABSTRACT
In March 2020, the FDA approved the use of COVID-19 convalescent plasma (CCP) as an investigational new drug for treatment of COVID-19. Since then, collection of CCP from COVID-19 recovered patients has been implemented in several donor centers across the country. Childrens Hospital Colorado rapidly put into practice a CCP collection protocol, necessitating the development and implementation of assays to evaluate SARS-CoV-2 antibodies in CCP units. We evaluated 87 separate units of CCP collected from 36 donors over two to four sequential donations using both antigen- binding assays for SARS-CoV-2 nucleoprotein and spike antigens, and a live virus focus reduction neutralization test (FRNT50). Our data shows that the majority of donors (83%) had a FRNT50 titer of 1:80 or greater, and 61% had a titer [≥] 1:160, which meet the FDAs criteria for acceptable CCP units. Additionally, our data indicates that analysis of antibodies to a single SARS-CoV-2 antigen is likely to miss a percentage of seroconverters; however, these individuals tend to have neutralizing antibody titers of <1:80. Of note, there was considerable variability in the short term, sustained antibody response, measured by neutralizing antibody titers, among our donor population.
