Food poisoning is often diagnosed based on a detailed history, including how long you've been sick, your symptoms and specific foods you've eaten. Your doctor will also perform a physical exam, looking for signs of dehydration.
Depending on your symptoms and health history, your doctor may conduct diagnostic tests, such as a blood test, stool culture or examination for parasites, to identify the cause and confirm the diagnosis.
For a stool culture, your doctor will send a sample of your stool to a laboratory, where a technician will try to identify the infectious organism. If an organism is found, your doctor likely will notify your local health department to determine if the food poisoning is linked to an outbreak.
In some cases the cause of food poisoning cannot be identified.
Symptoms
Abdominal pain: Most severe in inflammatory processes; painful abdominal muscle cramps suggest underlying electrolyte loss.
Vomiting: Major presenting symptom of S aureus, B cereus, or Norovirus
Diarrhea: Usually lasts less than 2 weeks.
Headache
Fever: May be an invasive disease or an infection outside the GI tract.
Stool changes: Bloody or mucous if invasion of intestinal or colonic mucosa; profuse rice-watery if cholera or a similar process.
Reactive arthritis: Seen with Salmonella, Shigella, Campylobacter, and Yersinia infection.