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Test Code 1746 Norovirus PCR, Molecular Detection, Feces

Method Name

Real-Time Polymerase Chain Reaction (PCR)/RNA Probe Hybridization

Specimen Type


Shipping Instructions

Place vial in a sealed plastic bag and ship ambient. Specimens received at other temperature will be rejected.

Specimen Required

Supplies: C and S Vial (T058)

Container/Tube: Commercially available transport system specific for recovery of enteric pathogens from fecal specimens (15 mL of non-nutritive transport medium containing phenol red as a pH indicator, either Cary-Blair, Para-Pak Culture and Sensitivity Media [C and S T058])

Specimen Volume: Representative portion of diarrheal stool, 1 gram or 5 mL

Collection Instructions:

1. Collect fresh stool and place in preservative within 1 hour of collection.

2. Visibly formed stool is not consistent with Norovirus gastrointestinal disease and should not be submitted for testing.

Specimen Stability Information

Specimen Type Temperature Time
Fecal Ambient 7 days

Clinical Information

Noroviruses, previously known as Norwalk-like viruses, are highly contagious RNA viruses that cause acute gastroenteritis (diarrhea, vomiting). Although 6 genogroups of norovirus have been identified, only 3 genogroups (genogroup: G1, G2, and G4) cause disease in humans. Furthermore, the majority of outbreaks have been associated with G1 and G2, with G2 being most common.(1)


Noroviruses are transmitted through close, personal contact with an infected individual or via the fecal-oral route, in which the virus becomes ingested in contaminated food or water. These viruses are extremely contagious, with fewer than 20 virions being able to cause disease.(1)


Once infected, the incubation period is typically short, between 24 and 72 hours. The onset of symptoms is abrupt, with vomiting and watery nonbloody diarrhea being common. Patients may also experience a low-grade fever, as well as headache and mild body aches.(1)


The diagnosis of norovirus infection can often be made on clinical grounds, and symptoms generally resolve in 24 to 48 hours. However, in certain patients, especially those who are immunocompromised or hospitalized, laboratory testing may be indicated for infection control purposes and to limit the use of antibiotics. Testing of diarrheal stool by real-time PCR allows for a rapid and sensitive means of detecting and differentiating norovirus G1 and G2 in clinical stool samples.

Reference Values



A positive result indicates that nucleic acid (RNA) from norovirus genogroups 1 and/or 2 was present in the clinical specimen.


A negative result suggests that nucleic acid (RNA) from norovirus genogroups 1 or 2 was absent in the clinical specimen.

Clinical Reference

1. Norovirus: Clinical Overview. Center for Disease Control and Prevention, 2013. Accessed 12/29/16. Available at

2. Echenique IA, Stosor V, Gallon L, et al: Prolonged norovirus infection after pancreas transplantation: a case report and review of chronic norovirus. Transpl Infect Dis 2016 18(1):98-104

Day(s) and Time(s) Performed

Monday through Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

87798 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LNORO Norovirus PCR, F 88701-8


Result ID Test Result Name Result LOINC Value
65170 Norovirus G1 PCR 54905-5
47553 Norovirus G2 PCR 54906-3