Updated 25 July 2018

Diagnosing gastroenteritis

A diagnosis of gastroenteritis will be made by your doctor, who will start off by asking you about your symptoms.

Diagnosing this condition is usually based on symptoms and medically examining the individual. It isn’t essential to know exactly which virus or bacteria caused the condition as treatment using specific drugs is rare.

However, it can be useful to tell your doctor whether you’ve been in contact with other symptomatic people who may have passed on a particular micro-organism.

It’s also important to mention whether you’ve been exposed to other common risk factors. For example, if you’ve travelled recently, it’s best to tell your doctor.

Determining whether gastroenteritis is caused by a rotavirus in a child is easily determined by laboratory testing of a stool sample. Tests to determine other viruses as causes aren’t routinely used as they’re both unnecessary and unlikely to significantly affect how the affected person is treated.

In cases of dysentery (where blood and mucus is present in the stool), a fresh stool specimen may be examined under the microscope for parasites such as Entamoebahistolytica (which causes amoebic dysentery). Alternatively, a bacterial culture may be done to identify the culprit.

Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology. December 2017.