Prozone Masks Elevated Sars-Cov-2 Antibody Level Measurements

Authors

Micaela N Sandoval
Samuel P McClellan
Stephen J Pont
Jessica A Ross
Michael D Swartz
Mark A Silberman
Eric Boerwinkle

Publication Date

1-1-2024

Journal

PLoS One

Abstract

We report a prozone effect in measurement of SARS-CoV-2 spike protein antibody levels from an antibody surveillance program. Briefly, the prozone effect occurs in immunoassays when excessively high antibody concentration disrupts the immune complex formation, resulting in a spuriously low reported result. Following participant inquiries, we observed anomalously low measurement of SARS-CoV-2 spike protein antibody levels using the Roche Elecsys® Anti-SARS-CoV-2 S immunoassay from participants in the Texas Coronavirus Antibody Research survey (Texas CARES), an ongoing prospective, longitudinal antibody surveillance program. In July, 2022, samples were collected from ten participants with anomalously low results for serial dilution studies, and a prozone effect was confirmed. From October, 2022 to March, 2023, serial dilution of samples detected 74 additional cases of prozone out of 1,720 participants' samples. Prozone effect may affect clinical management of at-risk populations repeatedly exposed to SARS-CoV-2 spike protein through multiple immunizations or serial infections, making awareness and mitigation of this issue paramount.

Keywords

Humans, SARS-CoV-2, COVID-19, Masks, Prospective Studies, Immunoassay, Antibodies, Viral, Spike Glycoprotein, Coronavirus