Performance evaluation of novel fluorescent-based lateral flow immunoassay (LFIA) for rapid detection and quantification of total anti-SARS-CoV-2 S-RBD binding antibodies in infected individuals
Farah M. Shurrab, Nadin Younes, Duaa W. Al‐Sadeq, Na Liu, Hamda Qotba, Laith J. Abu‐Raddad, Gheyath K. Nasrallah
Abstract
BackgroundA vast majority of the commercially available lateral flow immunoassay (LFIA) is used to detect SARS-CoV-2 antibodies qualitatively. Recently, a novel fluorescence-based lateral flow immunoassay (LFIA) test was developed for quantitative measurement of the total binding antibody units (BAUs) (BAU/mL) against SARS-CoV-2 spike protein receptor-binding domain (S-RBD).AimThis study aimed to evaluate the performance of the fluorescence LFIA FinecareTM 2019-nCoV S-RBD test along with its reader (Model No.: FS-113).MethodsPlasma from 150 reverse trancriptase–PCR (RT-PCR)-confirmed positive individuals and 100 prepandemic samples were tested by FincareTM to access sensitivity and specificity. For qualitative and quantitative validation of the FinCareTM measurements, BAU/mL results of FinCareTM were compared with results of 2 reference assays: the surrogate virus-neutralizing test (sVNT, GenScript Biotech, USA) and the VIDAS®3 automated assay (BioMérieux, France).ResultsFinecareTM showed 92% sensitivity and 100% specificity compared with PCR. Cohen's Kappa statistic denoted moderate and excellent agreement with sVNT and VIDAS®3, with values being 0.557 (95% CI: 0.32–0.78) and 0.731 (95% CI: 0.51–0.95), respectively. A strong correlation was observed between FinecareTM/sVNT (r = 0.7, p < 0.0001) and FinecareTM/VIDAS®3 (r = 0.8, p < 0.0001).ConclusionFinecareTM is a reliable assay and can be used as a surrogate to assess binding and neutralizing antibody response after infection or vaccination, particularly in none or small laboratory settings.