Performance evaluation of the PowerChek MERS (upE & ORF1a) real-time PCR kit for the detection of middle east respiratory syndrome coronavirus RNA

Abstract

Background: Molecular detection of Middle East respiratory syndrome coronavirus (MERS-CoV) using real-time reverse transcription (rRT)-PCR assays is the method of choice for diagnosis of MERS. We evaluated the performance of the PowerChek MERS (upE & ORF1a) real-time PCR Kit (PowerChek MERS assay; Kogene Biotech, Korea) a one-step rRT-PCR assay for the qualitative detection of MERS-CoV. Methods: We evaluated PowerChek MERS assay performance in comparison with nested RT-PCR and sequencing of the RNA-dependent RNA polymerase (RdRp) and N genes. To evaluate diagnostic sensitivity and specificity, 100 clinical specimens (50 positive and 50 negative for MERS-CoV) were simultaneously tested by using the PowerChek MERS and sequencing assays. Assay performance, including limit of detection and precision, was evaluated in vitro by using MERS-CoV RNA transcripts. Analytical specificity was evaluated with a diverse collection of 16 respiratory virus-positive clinical specimens and 14 respiratory bacterial isolates. Results: The 95% limits of detection of the PowerChek MERS assay for the upE and the open rading frame (ORF)1a were 16.2 copies/μL and 8.2 copies/μL, respectively. No cross-reactivity was observed. The diagnostic sensitivity and specificity of the PowerChek MERS assay were both 100% (95% confidence interval, 91.1-100%). Conclusions: The PowerChek MERS assay is a straightforward and accurate assay for detecting MERS-CoV RNA. The assay will be a useful tool for the rapid diagnosis of MERS and could prove especially important for MERS outbreak control.