Evaluation of a rapid diagnostic test for detection of SARS-CoV-2 antigen in nasopharyngeal swabs
Background and aims: Rapid and accurate diagnosis is essential to limit the spread of SARS-CoV-2 and for patient’s management. Currently, real-time reverse transcription polymerase chain reaction (RT-PCR) is the recommended laboratory test to detect SARS-CoV-2. However, the requirement of special instruments and skilled personnel have limited the use of this technique. Recently, several rapid antigen detection tests have been developed and used as frontline. The aim of this work was to assess the performances of STANDARD F COVID-19 Ag FIA Kit, a rapid fluorescence immunoassay for the detection of SARS-CoV-2 nucleoprotein antigens, in comparison to RT-PCR.
Materials and methods: Twenty-three nasopharyngeal swabs were collected and tested.
Results: Among the 20 positive RT-PCR samples, 9 were detected by the immunofluorescence assay, reporting an overall sensitivity of 45%. The sensitivity increased to 64% in the case of a high viral load, where all three target genes, RdRp, N, and E, were detected by RT-PCR.
Conclusions: A better antigen detection rate is associated with low Cycle threshold values which are inversely related to the viral load. STANDARD F COVID-19 Ag test cannot be considered as the frontline assay for COVID-19 diagnosis, but it might be used in association with clinical signs of patients to reduce the number of RT-PCR testing.
2. Zhang G, Zhang J, Wang B, et al. Analysis of clinical characteristics and laboratory findings of 95 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a retrospective analysis. Respir Res 2020; 21 74.
3. Mathuria JP, Yadav R, Rajkumar. Laboratory diagnosis of SARS-CoV-2 - A review of current methods. J Infect Public Health 2020; 13:901-905.
4. World Health Organization. Laboratory testing strategy recommendations for COVID-19: interim guidance, 21 March 2020. World Health Organization. https://apps.who.int/iris/handle/10665/331509.
5. Cerutti F, Burdino E, Milia MG, et al. Urgent need of rapid tests for SARS CoV-2 antigen detection: Evaluation of the SD-Biosensor antigen test for SARS-CoV-2. J Clin Virol 2020; 132:104654.
6. Dinnes J, Deeks JJ, Adriano A, et al. Rapid, point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. Cochrane Database Syst Rev 2020; 8:CD013705.
7. Centers for Disease Control and Prevention (CDC). Evaluation of rapid influenza diagnostic tests for detection of novel influenza A (H1N1) Virus - United States, 2009. MMWR Morb Mortal Wkly Rep 2009; 58:826-9.
8. Lambert-Niclot S, Cuffel A, Le Pape S, et al. Evaluation of a Rapid Diagnostic Assay for Detection of SARS-CoV-2 Antigen in Nasopharyngeal Swabs. J Clin Microbiol 2020; 58(8):e00977-20.
9. Scohy A, Anantharajah A, Bodéus M, et al. Low performance of rapid antigen detection test as frontline testing for COVID-19 diagnosis. J Clin Virol 2020; 129:104455.
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