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The RIDA® GENE Norovirus GI/GII assay, performed on the Applied Biosystems® 7500 Fast Dx System, is a real-time RT-PCR in vitro diagnostic test for the qualitative detection and differentiation of norovirus genogroup I (GI) and II (GII) RNA from raw or unpreserved stool specimens collected from individuals with signs and symptoms of acute gastroenteritis. The RIDA®GENE Norovirus GUGII assay is intended for use as an aid in the differential diagnosis of norovirus genogroup I and II infections in patients symptomatic for gastroenteritis in conjunction with clinical evaluation. laboratory findings, and epidemiological information. The assay aids in the detection and identification of norovirus infections as the cause of acute gastroenteritis in sporadic cases as well as in the context of outbreaks. Negative results do not preclude a norovirus infection and should not be used as the sole basis for diagnosis.

The RIDA®GENE Norovirus GI/GII assay, performed on the Applied Biosystems® 7500 Fast Dx System, is a real-time RT-PCR in vitro diagnostic test for the qualitative detection and differentiation of norovirus genogroup I (GI) and II (GII) RNA in human stool specimens. The assay also detects an internal control RNA (ICR, bacteriophage MS2) that is added to each sample prior to extraction. Sample preparation and amplification/real-time detection are completed on separate instruments. Each sample is pre-treated prior to extraction and sample processing is completed on the bioMérieux NucliSENS® easyMAG® instrument with bioMérieux NucliSENS® Nucleic Acid Extraction Reagents according to the manufacturer's instructions. The ICR serves to monitor inhibitors in the extracted specimen; it assures that adequate amplification has taken place and confirms that the nucleic acid extraction was sufficient. Following processing, either extracted nucleic acids or extracted negative control (NC) or positive control (PC) material is added to the Master-Mix. The assay is performed on an Applied Biosystems® 7500 FAST Dx System. The detection is performed in a one-step real-time RT-PCR format where the reverse transcription is followed by the PCR in the same reaction tube under optimized conditions. The isolated RNA is transcribed into cDNA by a reverse transcriptase. Gene fragments specific for norovirus GI and GII are subsequently amplified by real-time PCR. The amplified targets (ORF1/ORF2 conserved junction region) are detected with hydrolysis (TaqMan®) probes, which are labeled at one end with a quencher and at the other end with a fluorescent reporter dye (fluorophore). In the presence of a target, the probe(s) hybridize to it and during the extension step the Taqpolymerase breaks the reporter-quencher proximity. Upon excitation by the Applied Biosystems® 7500 FAST Dx's halogen light source, the reporter emits a distinct fluorescent signal which is detected by the optical unit of the Applied Biosystems® 7500 FAST Dx System. Hence, depending on the target sequence present (genogroup GI, GII or both), one, two or none of the reporters on the norovirus specific probes emits light to be detected by the instrument. Fluorophores are chosen in a way that their excitation and emission wavelengths do not overlap and signals are readily discriminated by the software. The fluorescence signal increases with the amount of formed amplicons.

The RIDASCREEN® Norovirus 3td Generation test is a qualitative enzyme immunoassay (EIA) intended for the detection of selected genogroup I (GI.1, GL.2, GI.3, GI.4, GL.7) and genogroup II (GII.1, GII.2, GII.3, GII.4, GII.5, GII.6, GII.7, GII.8, GII.10, GII.12, GII.13, GII.14, GII.17) norovirus strains in human feces as an aid in investigating the cause of acute gastroenteritis outbreaks. The likelihood of detecting a norovirus outbreak by use of the RIDASCREEN® Norovirus 3td Generation test improves as the number of patients tested during an outbreak increases, as well as when quality of the specimens increases. Preliminary identification of norovirus as the cause of an acute gastroenteritis outbreak by RIDASCREEN® Norovirus 3td Generation testing should be confirmed by reference methods as appropriate, particularly if only a limited number of positive samples are associated with a suspected outbreak. Additional testing of negative samples by other methods should be performed if norovirus is strongly suspected as the cause of an acute gastroenteritis outbreak.

RIDASCREEN® Norovirus 3rd Generation test is a solid phase sandwich-type EIA for the detection of genogroups GI and GII noroviruses in stool samples. Microwell strips are coated with a mixture of GI and GII norovirus specific monoclonal antibodies. An aliquot of fecal suspension is added to the microwell together with biotinylated monoclonal norovirus antibodies. After washing, streptavidin peroxidase conjugate is added. Norovirus antigens that are present in the stool sample are captured in a sandwich complex of the immobilized antibodies, the norovirus antigens and the monoclonal antibodies conjugated with the biotin-streptavidin-peroxidase complex. Unbound streptavidin peroxidase conjugate is removed by washing and a chromogenic colorless substrate solution (hydrogen peroxide/TMB) is added. The substrate is hydrolyzed by any bound peroxidase, changing the chromogen to a blue color. Stopping the reaction with acid converts the blue to a yellow color indicating the presence of norovirus antigens. Test results are read photometrically; intensity significantly above background levels is indicative of the presence of Norovirus antigen in the specimen or control. The RIDASCREEN® Norovirus 3rd Generation test does not identify specific norovirus strains.