1. Evaluation of qualitative and semi-quantitative cut offs for rapid diagnostic lateral flow test in relation to serology for the detection of SARS-CoV-2 antibodies: findings of a prospective study
- Author
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Maddalena, Peghin, Giulia, Bontempo, Maria, De Martino, Alvisa, Palese, Valentina, Gerussi, Elena, Graziano, Martina, Fabris, Federica, D'Aurizio, Francesco, Sbrana, Andrea, Ripoli, Francesco, Curcio, Miriam, Isola, and Carlo, Tascini
- Subjects
Immunoassay ,Adult ,SARS-CoV-2 ,COVID-19 ,Rapid diagnostic test ,Antibodies, Viral ,Sensitivity and Specificity ,Antibodies ,CLIA ,ELISA ,Lateral flow immunoassay ,POC ,RDT ,Serology ,Humans ,Prospective Studies ,Immunoglobulin M ,Immunoglobulin G ,Infectious Diseases ,Viral - Abstract
Background: There is limited information to compare the qualitative and semi-quantitative performance of rapid diagnostic tests (RDT) and serology for the assessment of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, the objective of the study was (a) to compare the efficacy of SARS-CoV-2 antibody detection between RDT and laboratory serology, trying to identify appropriate semi-quantitative cut-offs for RDT in relation with quantitative serology values and to (b) evaluate diagnostic accuracy of RDT compared to the NAAT gold standard in an unselected adult population. Methods: SARS-CoV-2 antibodies were simultaneously measured with lateral flow immunochromatographic assays (LFA), the Cellex qSARS-CoV-2 IgG/IgM Rapid Test (by capillary blood), the iFlash-SARS-CoV-2 IgG/IgM chemiluminescent immunoassay (CLIA) (by venous blood) and the nucleic acid amplification test (NAAT) in samples from in- and out-patients with confirmed, suspected and negative diagnosis of coronavirus disease 2019 (COVID-19) attending Udine Hospital (Italy) (March-May 2020). Interpretation of RDT was qualitative (positive/negative) and semi-quantitative based on a chromatographic intensity scale (negative, weak positive, positive). Results: Overall, 720 paired antibody measures were performed on 858 patients. The qualitative and semiquantitative agreement analysis performed in the whole sample between LFA and CLIA provided a Kendall’s tau of 0.578 (p Conclusion: The RDT used in our study can be a non-invasive and reliable alternative to serological tests and facilitate both qualitative and a semi-quantitative antibody detection in COVID-19.
- Published
- 2022
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