Development of loop-mediated isothermal amplification assay for detection of human coronavirus-NL63

Human coronavirus NL63 was identified in 2004 in the Netherlands. Due to the high prevalence and world-wide distribution of this pathogen, it is essential to develop a sensitive and specific detection assay suitable for use in a routine diagnostic laboratory. Techniques based on PCR or real-time PCR are laborious and expensive. Detailed analysis of the HCoV-NL63 genome permitted the identification of a conserved nucleic acid sequential motif, which was sufficient for the design of a loop-mediated isothermal amplification (LAMP) assay. Evaluation of the method showed that the test is specific to HCoV-NL63 and that it does not cross-react with other respiratory viruses. The detection limit was found to be 1 copy of RNA template per reaction in cell culture supernatants and clinical specimens.