Whole stool is the preferred specimen for diagnosing norovirus in the laboratory. When food or water is the suspected cause of an outbreak, collect samples soon after exposure and refrigerate them immediately.
Clinical specimens
Stool
Whole stool is preferred; stool in Cary-Blair transport medium can also be tested.
In an outbreak investigation:
- collect from at least 5 ill people in the acute phase — up to 72 hours after symptoms start — while stool is still liquid or semisolid;
- collect more specimens if sampling after the acute phase or after symptoms have ended (up to 7–10 days after onset), or in large or long-lasting outbreaks.
Shipping: label each sample with a unique identifier, put it in a leak-proof plastic container sealed in a separate bag, and pack it on frozen refrigerant packs in an insulated, waterproof polystyrene box.
Storage:
| Tested within | Keep at |
|---|---|
| 2–3 days of collection (whole stool, Cary-Blair) | refrigerated, 39°F (4°C) |
| 2–3 weeks (stool) | refrigerated, 39°F (4°C) |
| Later, or for archiving | frozen, ideally at −94°F (−70°C), otherwise −4°F (−20°C) |
Vomit
Vomitus can be collected alongside stool in an outbreak, collected and shipped the same way, but always stored frozen (−4°F / −20°C or −94°F / −70°C).
Serum
Not recommended for routine diagnosis. For special studies, paired sera can show a more than fourfold rise in IgG against noroviruses:
- acute-phase serum within the first 5 days of symptoms;
- convalescent-phase serum in the third to fourth week;
- stored frozen at −4°F (−20°C).
More: CDC's 2011 norovirus outbreak management and prevention guidelines.
Food, water and surfaces
Norovirus can be found in water, food and the environment, but must first be concentrated or extracted.
- Water: large volumes — up to 100 liters — are passed through special filters; CDC has validated methods for clean and surface water. Store refrigerated or on ice at 39°F (4°C).
- Food: the U.S. Food and Drug Administration has validated methods for foods including shellfish, leafy greens and berries. Store frozen at −4°F (−20°C).
- Surfaces: swabs of doorknobs, handrails and kitchen counters can be tested, but virus levels are often low and may not be detected — interpret results cautiously, alongside the epidemiologic evidence.
Resources
- CDC: waterborne disease surveillance
- Oregon Health Authority: How to Collect a Stool Specimen, a video, and the It-Kit
- Minnesota Department of Health: Submitting a Stool Sample
Sources
Based on "Norovirus Specimen Collection," Centers for Disease Control and Prevention; a work of the United States government in the public domain. The source's stock laboratory photograph is not reproduced.
ライセンス： CC0 1.0（パブリックドメイン） · 出典 www.cdc.gov
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