Evaluation of a flow cytometry-based surrogate assay (FlowSA) for the detection of SARS-CoV-2 in clinical samples

IF 1.6 Q4 INFECTIOUS DISEASES

Journal of clinical virology plus Pub Date : 2025-02-01 DOI:10.1016/j.jcvp.2025.100204

Vinit Upasani , Marjolein Knoester , Daniele Pantano , Lili Gard , Jolanda M. Smit , Bernardina T.F. van der Gun , Adriana Tami , Izabela A. Rodenhuis-Zybert

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引用次数: 0

Abstract

Introduction

The current diagnostic methods for SARS-CoV-2 rely on quantitative RT-PCR. However, the presence of viral RNA in samples does not necessarily reflect the presence of an infectious virus. Therefore, the reliable detection of infectious SARS-CoV-2 in clinical samples is necessary to limit viral transmission.

Methods

We developed a flow cytometry-based surrogate assay (FlowSA), wherein the presence of infectious SARS-CoV-2 was detected using virus nucleocapsid-specific antibodies.

Results

We showed that FlowSA allows the detection of a wide range of viral titers of multiple SARS-CoV-2 variants. Furthermore, the assay was successfully used to detect infectious SARS-CoV-2 in nasopharyngeal swabs from SARS-CoV-2 positive individuals, including those with high Ct values. Notably, FlowSA identified the presence of infectious SARS-CoV-2 in biological specimens that scored negative for cytopathic effect (CPE) in cell culture and would otherwise be considered negative.