Article in Japanese

Norovirus pseudo-outbreak in neonatal intensive care unit∼The high false positive rate of rapid immunochromatography testing for norovirus from neonatal stool∼

Nobumasa TAKAHASHI, Tomoaki WADA, Masanori IKEDA

Norovirus is one of the causes of viral enterocolitis and also of nosocomial infections. A rapid detection test was recently released which uses immunochromatography (QuickNavi^TM-Norovirus). It is increasingly used as a diagnostic method. For early treatment and prevention from nosocomial infection, it is important to diagnose norovirus infection rapidly in neonates as well as in adults and children. But it is unknown whether or not the rapid detection test is useful for neonates. We report a high rate of false-positive readings by rapid detection test from neonatal stool. Ten of 14 neonates (18 of 40 samples) were found to be positive for norovirus by rapid detection test in our NICU. But all seven samples which were found to be positive by rapid detection test were found to be negative by reverse transcription polymerase chain reaction. The reason for the high rate of false positives is unknown. We speculate that some factors of neonatal stool cause a non-specific reaction in immunochromatography assays. The non-specific reaction continues for some weeks after birth. The reaction continues longer in preterm infants than in full term infants. We recommend studies of the reason for the high rate of false positives and improvement of the rapid detection test. At the present stage, we should use immunochromatography assays very carefully to diagnose neonatal norovirus infection.

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Department of Pediatrics, Fukuyama Medical Center

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Received	December 17, 2009
Accepted	June 3, 2010

22 (3)：223─226,2010