Public Health Division

Lab Test Details

Norovirus, Real-Time RT-PCR
Updated	4/1/2025
Search Terms	Astrovirus; Calicivirus; Norovirus (I and II); Sapovirus; Rotavirus; Gastrointestinal Viruses; Norwalk
How to Order	On the Virology/Immunology Test Request Form (OHA0042), in the "Molecular" section, check the "MOL NOV: Norovirus RT-PCR" box. If the specimen is associated with an identified outbreak, include the outbreak number in the Outbreak Number box on the Test Request Form. If the specimen is associated with a study, include the study identification in the Study box on the Test Request Form.
Availability	With approval from the Acute and Communicable Disease Program or Local Public Health Authorities
Performed	As needed
Time to Reporting	Within 7 working days after receipt of specimen
Public Health Data	Data from norovirus testing and genetic sequencing are shared with the Centers for Disease Control and Prevention (CDC) as part of the CaliciNet Surveillance Network.
CPT Code	87798 87798 repeated for each additional gastrointestinal pathogen test performed

Specimen Collection Details
Collection	Ideally, collect specimens in the acute phase of illness while stool is still liquid or semi-soft (typically up to 72 hours after symptom onset). Specimens may be collected up to 14 days after symptom onset; sensitivity decreases 7-14 days after illness onset but can remain detectable. Preferred specimen types: Raw stool in a clean, screw-top plastic container Stool in Cary Blair enteric pathogen transport media Acceptable specimen: Vomit in a clean screw top plastic container.
Optimal Volume	Solid or Liquid Stool; Vomit - 5 gm or 5 mL Stool in Cary Blair enteric pathogen transport media to the fill line on vial (approx. 5 gm or 5 mL)
Minimum Volume	Solid Stool - 2 gm Liquid Stool; Vomit - 2 mL Approx. 1.0 mL stool in Cary Blair enteric pathogen transport media
Handling	Store all specimen types at refrigerated temperatures (2-8°C) pending transport. Transport as soon as possible after specimen collection. Avoid extreme temperatures.
Transport	Package all specimen types with fully frozen ice packs to maintain refrigerated temperatures during transport. Raw stool or vomit: Specimens should be received at OSPHL within 5 days of collection. Stool in Cary Blair: Specimens must be received at OSPHL within 4 days of collection. Avoid extreme temperatures.
Rejection Criteria	Raw stool and vomit: Specimens received more than 10 calendar days after specimen collection. Stool in Cary Bair: Specimens received more than 4 days after specimen collection. Specimens are subject to the requirements of the OSPHL Specimen Submission Policy (pdf).
Comments	Original material submitted for testing is retained for 7 calendar days after receipt at the laboratory. Norovirus is a primary cause of viral gastroenteritis. Other gastrointestinal viruses (astrovirus, sapovirus, and rotavirus) will only be tested upon request and approval from state or local public health authorities. If bacterial pathogens are suspected, follow the instructions for BioFire^® FilmArray^® Multiplex Gastrointestinal PCR Panel or Enteric Pathogen Culture. Specimens testing positive for norovirus are testing using Sanger or Next Generation Sequencing for public health surveillance.

Method Details
Methodology	Real-Time Reverse-Transcription Polymerase Chain Reaction
Performance Specifications	Method Performance Specifications determined by the Centers for Disease Control and Prevention (CDC). Please contact the CDC for specifications if needed.

Change Log
4/1/2025	Review as new; Comprehensive changes
5/23/2023	Edit How to Order, CPT Code, Comments