Title Evaluation of rapid immunochromatographic tests for norovirus in neonatal and infant fecal specimens

Objectives: The accuracy of rapid immunochromatographic tests for norovirus in neonatal and infant fecal specimens has not been sufficiently evaluated. This study evaluated the diagnostic performance of two norovirus rapid immunochromatographic kits (QuickNavi-Norovirus® and QuickNavi-Norovirus 2®; Denka Seiken, Niigata, Japan) for neonatal and infant fecal specimens. Methods: We collected infant fecal specimens every month from 0 to 12 months old. Fecal specimens were tested using the two types of rapid immunochromatographic kit. Real-time reverse transcription polymerase chain reaction (RT-PCR) testing was employed for all specimens as the standard for norovirus detection. Diagnostic performances of the two kits were calculated and compared. Results: A total of 346 fecal specimens were evaluated. Specificities of the QuickNavi-Norovirus and QuickNavi-Norovirus 2 were 80% (275/343) and 99% (339/343), respectively. Specificity of the QuickNavi-Norovirus in the neonatal period was only 33% (23/70), but this gradually increased with postnatal age. By 4 months old, specificity had increased to 93%. With regard to QuickNavi-Norovirus 2, specificity was over 94% from 0 through 12 months old. Conclusions: QuickNavi-Norovirus 2 offered improved performance, and appears more useful than QuickNavi-Norovirus to diagnose norovirus infections in the neonatal and infant periods. Introduction Norovirus is a major pathogen in epidemic gastroenteritis. Rapid diagnosis of norovirus infection is important for the early treatment, prevention, and control of outbreaks. In neonatal intensive care units (NICUs), rapid diagnosis of norovirus is particularly important. Nosocomial norovirus outbreaks in NICUs have been reported [1] and the clinical course can vary among patients, occasionally resulting in necrotizing enterocolitis [2, 3]. Rapid immunochromatographic tests for norovirus are now being used with increasing frequency. RIDA® QUICK Norovirus (R-Biopharm, Darmstadt, Germany),