Context.— Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a recently emerged, currently pandemic virus, and the etiological agent of coronavirus disease 2019 (COVID-19). Clinical testing for antibodies to SARS-CoV-2 has rapidly become widespread, but data regarding the inter-laboratory performance of these serologic assays are limited.

Objective.— To describe the development and initial results of the College of American Pathologists (CAP) SARS-CoV-2 Serology Survey.

Design.— Members from the CAP Microbiology and Diagnostic Immunology and Flow Cytometry Committees formed a working group to support development of a new proficiency testing survey for anti-SARS-CoV-2 antibody assays. Supplemental questions in the survey assessed the state of SARS-CoV-2 serologic testing among participating laboratories as of July 2020. Results were analyzed for agreement by immunoglobulin isotype tested, assay manufacturer, and methodology.

Results.— A total of 4,125 qualitative results were received from 1,110 laboratories participating in the first survey. Qualitative agreement for assays measuring anti-SARS-CoV-2 total antibodies or IgG was greater than 90% for all three samples in the survey. Qualitative agreement for IgM and IgA for the negative sample was greater than 95%, but lacked consensus for the other two samples.

Conclusions.— These initial data suggest overall excellent agreement and comparable performance for most qualitative anti-SARS-CoV-2 IgG and total antibody assays across all participating clinical laboratories, regardless of specific target antigen or assay methodology.

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Author notes

Elitza S. Theel reports participation on an Advisory Board for Roche Diagnostics, consulting for Accelerate Diagnostics and Siemens, and sponsored research funding from Roche Diagnostics and Ortho-Clinical Diagnostics. Daniel D. Rhoads performs sponsored research from IVD companies such as BD, Bio-Rad, and Roche; but he has received no funding for SARS-CoV-2 immunology studies. The other authors have no relevant financial interest in the products or companies described in this article.

Susan L. Fink was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under awards K08AI119142, R21AI130281, R21AI131269 and R21AI153487. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.