Development of a Recombinase Polymerase Amplification Assay for Detection of Epidemic Human Noroviruses

Moore, Matthew D.; Jaykus, Lee-Ann

was able to detect 13/17 of the strains tested and, compared to the RT-PCR "gold standard, " had a sensitivity and specificity of 100% and 80%, respectively. A different NASBA assay design targeting the ORF1-ORF2 junction and using the JJV2F and COG2R primers 14, 15 reportedly had higher analytical sensitivity, approximately 90% concordance with other assays, and reduced time-to-result (90 min) 16 . The first human norovirus LAMP assay targeted a similar genome region to the RT-RPA, was designed to detect both GI and GII viruses, and had a detection limit of 2-3 LGC/25 μ l reaction. Sensitivity and specificity approached 100% and results were achieved in 60-90 min 11 . Yoda et al. 17 designed their own LAMP assay targeting the ORF1-ORF2 junction and were able to improve on the detection limit (to 1-2 LGC/25 μ l reaction) and increase inclusivity by design changes. In another study, Iturriza-Gomara et al. 18 evaluated a commercial RT-LAMP for norovirus detection relative to an RT-PCR, finding a slightly lower sensitivity for the GI RT-LAMP but a higher sensitivity for the RT-LAMP assay. Newer LAMP designs are facilitating colorimetric endpoints and can be used even for genotyping 19, 20 .