Special Precautions/Comments:

N.B.  Norovirus testing is performed on request when there is an outbreak scenario – Infection control or Microbiology medics will inform the laboratory of suspect wards/locations.

Samples may not be tested due to Control of Infection Policies. No further norovirus testing will be performed if:

• A location has produced 6 negative results (location not considered a Norovirus outbreak).
• A location has produced 2 positive results (location considered an outbreak).

Interferences: Faecal samples that are heavily blood stained ( >10% v/v), mucoid (>5% w/v), or fatty (>5% w/v) may give invalid or false negative results.

Patients who have used over-the-counter anti-inflammatory drugs and prescription products have produced false negative or invalid results. Including, but not limited to: amoxicillin, ampicillin, hydrocortisone, ibuprofen, Imodium, metronidazole and Rexall Mineral oil laxative.

Method:  Automated real-time polymerase chain reaction (PCR). Calibration: N/A.  EQA scheme: QCMD and NEQAS. IQC: Each assay cartridge contains a Probe Check Control (PCC) (Cepheid). Norovirus External Positive Control (ZeptoMetrix NATtrol Norovirus External Run Control)

Interpretation: Results will be reported as DETECTED (positive), INVALID, or Not detected (negative).  A negative result does NOT fully exclude infection. Samples resulted as Invalid will be repeated and a further report issued. Samples may remain invalid due to inhibitory substances within the sample.

Additional Information:

Background information:  Noroviruses are highly contagious and are able to cause outbreaks, especially in crowded environments such as hospitals and nursing homes. Due to the severity of dehydration that can result, infections can present a significant risk to the elderly, infants and patients with underlying disease. Norovirus can persist in the environment and can resist several forms of disinfection, so the quick detection of them as a cause of gastroenteritis is essential for the implementation of effective infection control measures.

The Xpert Norovirus Assay is intended to aid in the diagnosis of norovirus infections when used in conjunction with clinical evaluation, laboratory findings, and epidemiological information. The assay also aids in the detection and identification of norovirus infections in the context of outbreaks.

 Keywords: Vomiting, diarrhoea, noro, PCR, outbreak, infection control, gastrointestinal