Diagnosis of norovirus infection:

Specific diagnostic testing isn't usually necessary to identify the exact viral cause of viral gastroenteritis. Your doctor will likely be able to diagnose your illness by asking about a person's medical history, including questions about:

• Symptoms
• Current medical conditions
• Current medications
• Family history of any medical conditions
• Recent travel history
• Recent food and liquid consumption.

If there has been an outbreak of norovirus infection, your doctor or the public health department may ask you additional questions about your activities in order to help identify the source of contamination.

If necessary, noroviruses can be identified in stool samples under an electron microscope. A reverse transcriptase polymerase chain reaction test (RT-PCR assay) also can detect noroviruses in food, in water, in stool samples and on environmental surfaces. These tests isolate and replicate the suspected virus' genetic material for analysis.