Food poisoning is diagnosed clinically and your doctor will not recommend any tests if the symptoms are mild to moderate. Most people with food poisoning improve with treatment in a few days at home and may not even need to visit a doctor.
You may need to consult a doctor for a diagnosis if:
Medical history and physical examination: To diagnose the cause of food poisoning, the doctor will take a detailed history and do physical examination. The doctor may ask questions such as:
The doctor will examine you to look for signs of dehydration and possible complication because of dehydration such as low blood pressure, poor peripheral pulses, and blood infection (sepsis). In infants, the doctor will examine the soft spot on the head (fontanelle) to look for dehydration (it becomes sunken if the infant is dehydrated).
Stool sample: Tests are usually not done in people with food poisoning. The doctor may recommend stool sample to investigate for bacteria or parasites if:
Blood tests: Blood tests are usually done if the symptoms are severe and you are admitted in a hospital. Tests may be done to rule out complications due to dehydration such as electrolyte imbalance, increase in blood urea, low blood sugar (more common in young children), and infection in blood (sepsis).