How is food poisoning diagnosed?

Most food poisoning is mild and passes in a few days, so most people don't go to a doctor for a diagnosis. You can often diagnose food poisoning yourself if others who ate the same food as you also become ill.

If you do go to your doctor, he or she will make the diagnosis based on your symptoms, a physical exam and your medical history. Your doctor will ask where you have been eating and whether anyone who ate the same food has the same symptoms.

Sometimes the following tests are done:

• A stool culture may be done if your doctor suspects that you have eaten contaminated food, your symptoms are severe or the diagnosis is uncertain.
• Blood tests may be done to help find out whether the food poisoning is caused by bacteria or to rule out other causes. A complete blood count and a chemistry screen can help show whether you are severely ill or dehydrated.
• If you are pregnant or have an impaired immune system and have been exposed to toxoplasmosis, you may need a toxoplasmosis test.

Your doctor may need to report your condition to the health department. This is done to help the government track the condition and identify possible outbreaks.