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. 2024 Mar 28;19(3):e0301232.
doi: 10.1371/journal.pone.0301232. eCollection 2024.

Prozone masks elevated SARS-CoV-2 antibody level measurements

Micaela N Sandoval  1 , Samuel P McClellan  2 , Stephen J Pont  3 , Jessica A Ross  1 , Michael D Swartz  4 , Mark A Silberman  2 , Eric Boerwinkle  1
Affiliations

Prozone masks elevated SARS-CoV-2 antibody level measurements

Micaela N Sandoval et al. 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.

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Conflict of interest statement

The authors have declared no competing interest.

Figures

Fig 1
Fig 1. Dilution protocol for anti-SARS-CoV-2 spike protein immunoassay, implemented October 12, 2022.
See this image and copyright information in PMC

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