Answer: The stomach flu is diagnosed by a physical exam or stool sample test.
Viral gastroenteritis is usually diagnosed based on symptoms. A test may be done on a stool sample to determine if a child has rotavirus or adenovirus but tests usually aren’t done for other viruses. The doctor may want to test for the new Norovirus GII.4 Sydney strain if that is suspected. But, most of the time, we have no idea which particular virus we have. Your doctor might recommend a stool sample test for you in order to rule out a bacterial or parasitic infection. The doctor will also want to rule out appendicitis and strep throat. It is very important to clean with a product that actually kills norovirus when a stomach bug is in your home such as the Clorox® Hydrogen Peroxide Spray and Clorox Hydrogen Peroxide Wipes.
--Annie Pryor, Ph.D.