Evaluation of two commercial molecular diagnostic assays: The Xpert Norovirus and the TRCReady NV.

ABSTRACT

INTRODUCTION: Norovirus is highly contagious, and a few particles of this virus are sufficient to make people sick. It is desirable to develop quick and accurate laboratory methods to detect norovirus. METHODS: We evaluated two commercial molecular diagnostic assays, the Xpert Norovirus and the TRCReady NV, using clinical fecal samples. A reference method was performed using in-house real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR). RESULTS: The results of the real-time RT-PCR analysis of 60 suspected cases of norovirus infection showed 5 cases of Genogroup I (GI) positives and 21 cases of GII positives, among which was 1 GI and GII coinfection. The viral titers of the norovirus-positive samples ranged from 1.54 × 101 to 3.14 × 108 copies/µL. Norovirus GII.17 (12 cases, 48%) was the most frequently detected genotype in this study, followed by GII.4 (6 cases, 24%), GII.13 (2 cases, 8%), GI.2 (2 cases, 8%), GI.3 (2 cases, 8%), GI.1 (1 case, 4%), and GII.2 (1 case, 4%). The kappa coefficient was 1.000 (95% CI 1.000-1.000) for Xpert Norovirus and 0.966 (95% CI 0.896-1.000) for TRCReady NV, indicating a strong agreement. CONCLUSIONS: Norovirus detection using Xpert Norovirus and TRCReady NV is highly useful for diagnosis and infection control because these assays are easy to operate, quick, and exhibit almost the same performance as that of real-time RT-PCR.