Performance and clinical validation of the RealStar(®) MERS-CoV Kit for detection of Middle East respiratory syndrome coronavirus RNA

BACKGROUND: A highly pathogenic human coronavirus causing respiratory disease emerged in the Middle East region in 2012. In-house molecular diagnostic methods for this virus termed Middle East respiratory syndrome coronavirus (MERS-CoV) allowed sensitive MERS-CoV RNA detection in patient samples. Fast diagnosis is important to manage human cases and trace possible contacts. OBJECTIVES: The aim of this study was to improve the availability of existing nucleic acid amplification-based diagnostic methods for MERS-CoV infections by providing a real-time RT-PCR kit, including an internal control and two target regions recommended by the World Health Organization (WHO). And to validate this kit (RealStar(®) MERS-CoV RT-PCR kit 1.0, Altona Diagnostics GmbH, Hamburg, Germany) using clinical samples of one MERS-CoV case from Munich and respiratory samples of patients with other respiratory diseases. STUDY DESIGN: An internal amplification control was included into the RT-PCR assays targeting the genomic region upstream of the Envelope gene (upE) and within open reading frame (ORF) 1A. Based on these assays, a ready-to-use real-time RT-PCR kit featuring both the upE and ORF1A assays was developed, validated and compared to the established in-house versions. RESULTS: The performance of both RT-PCR assays included in the kit is comparable to the in-house assays. They show high analytical sensitivity (upE: 5.3 copies/reaction; ORF1A: 9.3 copies/reaction), no cross-reactivity with other respiratory pathogens and detected MERS-CoV RNA in patient samples in almost the same manner as the in-house versions. CONCLUSION: The kit is a valuable tool for assisting in the rapid diagnosis, patient management and epidemiology of suspected MERS-CoV cases.