Selected article for: "false negative and negative rate"

Author: Julia Alcoba-Florez; Rafaela Gonzalez-Montelongo; Antonio Inigo-Campos; Diego Garcia-Martinez de Artola; Helena Gil-Campesino; Laura Ciuffreda; Agustin Valenzuela-Fernandez; Carlos Flores
Title: Fast SARS-CoV-2 detection by RT-qPCR in preheated nasopharyngeal swab samples
  • Document date: 2020_4_11
  • ID: icpwfyss_18
    Snippet: Out of the 41 COVID-19/SARS-CoV-2 positive VTM samples, only five did not yield amplification for the Egene with the Direct treatment. Regarding the ACTB gene amplification results on the extracted RNA of these five samples, we did not observe significant differences when compared with those from the other COVID-19/SARS-CoV-2 positive samples (average Ct of 27.6 ± 1.2 and 26.9 ± 1.6, respectively; p=0.457). However, their Ct values for the E-ge.....
    Document: Out of the 41 COVID-19/SARS-CoV-2 positive VTM samples, only five did not yield amplification for the Egene with the Direct treatment. Regarding the ACTB gene amplification results on the extracted RNA of these five samples, we did not observe significant differences when compared with those from the other COVID-19/SARS-CoV-2 positive samples (average Ct of 27.6 ± 1.2 and 26.9 ± 1.6, respectively; p=0.457). However, their Ct values for the E-gene were significantly larger (average Ct of 34.0 ± 2.0 and 25.7 ± 4.9, respectively; p=0.0007). Therefore, we considered these five samples as false negatives, corresponding to a false negative rate in the Direct treatment of 12% (95% confidence interval [CI]= 5-28). Considering the 36 samples that were COVID-19/SARS-CoV-2 positive by the two methods, there was an average increase in the E-gene Ct by the Direct method of 6.1 (± 1.6) compared to that obtained by a regular RNA extraction. None of the COVID-19/SARS-CoV-2 negative VTM samples was classified as a positive by the Direct treatment. Therefore, the Direct method yielded a sensitivity, specificity and accuracy of 87.8% (95% CI= 73.8-95.9), 100% (95% CI=92.8-100), and 99.9% (95% CI= 95.7-100), respectively.

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