Commercial COVID 19 serial seroconversion panel for validation of SARS CoV 2 antibody assays

Background Seroconversion panels (SCP) are an important tool for investigating antibody responses and developing serological assays. A SCP was generated from a single SARS-CoV-2 positive plasma donor over 87 days. Methods This SCP was tested against five SARS-CoV-2 antibody tests (IgG, IgM and total Ig). All test kits utilized recombinant antigens that are specific to SARS-CoV-2. Results The SCP showed IgG responses for SARS-CoV-2 after day 50. IgM levels peaked on day 50 (prior to IgG) and declined in subsequent samples. Conclusion This SCP is a useful tool for validation of SARS-CoV-2 antibody assays. ### Competing Interest Statement Francisco Belda is a full-time employee of Grifols. Robin Cherenzia and Michael Crowley are full-time employees of Access Biologicals. ### Funding Statement This study was supported by Grifols (Barcelona, Spain) and Access Biologicals (Vista, CA, USA). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The patient samples were collected with informed consent, under an approved IRB protocol and in compliance with all applicable regulatory guidelines. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data referred to in the manuscript are available from the corresponding author upon reasonable request.