Evaluating the performance of two rapid antigen detection tests in diagnosis of SARS- COV- 2 infection

Document Type : Original Article


1 Clinical and chemical pathology department Cairo university

2 Clinical and Chemical Pathology Department, Faculty of Medicine ,Cairo University

3 Clinical and Chemical Pathology Department ,Faculty of Medicine ,Cairo University

4 Clinical and Chemical Pathology Department .Faculty of Medicine ,Cairo University

5 Clinical and Chemical Pathology Department ,Faculty of Medicine, Cairo University

6 Clinical and Chemical Pathology ,Faculty of Medicine ,Cairo University


Background:Rapid antigen detection tests for SARS-CoV-2 infection could promote the clinical and public health policies to handle the COVID-19 pandemic. Rapid antigen detection and molecular approaches could expand entry to checking and initial evidence of issues and playing an essential role in public health managing choices that may decrease the transmission. Objectives: We evaluated the diagnostic accurateness of couple of rapid antigen recognition tests equated with the molecular-based assays for verdict of SARS-CoV-2 infection. Methods: The 100 nasopharyngeal swabs were verified by the SARS-CoV-2 RT-PCR kit as a gold standard for COVID-19 recognition. SARS‐CoV‐2 antigen (Ag) was evaluated in the nasopharyngeal swabs using iFlash and UNICELL-2019-nCoV antigen methods. The iFlash-2019-nCoV antigen assay, which is a chemiluminescent immunoassay (CLIA), was used to qualitatively determine the nucleocapsid protein antigen, where the other one was used to identify the nucleocapsid protein antigen by lateral flow immunofluorescent test. Results: Out of the 100 samples, 62% were positive by RT-PCR. Amongst 62 confirmed COVID-19 cases, 43 (69.4%) were positive by iFlash and 40 samples (64.5%) were positive by the UNICELL-2019-nCoV antigen assay. The specificity of both I Flash-2019-nCoV antigen assay & UNICELL-2019-nCoV antigen assay with RT-PCR were 100% and sensitivity were 69.35 and 64.52%, respectively. This sensitivity was augmented to 100% compared with the PCR with Ct-value of ≤25 and specificity of 80.28 and 84.51%, respectively. Conclusion: Antigen detection rapid diagnostic tests may be motivating in the initial stage of the infection when the viral load is elevated, and the risk of SARS‐CoV‐2 transmission be high.


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