If your child has symptoms of lactose intolerance, your specialist at Orlando Health Arnold Palmer Hospital Center for Digestive Health and Nutrition will want to rule out conditions with similar symptoms such as irritable bowel syndrome and celiac disease. They will do a physical exam and perform one or more of the following tests:


  • Hydrogen breath test. During this test, your child gives a breath sample by blowing into a tube. The sample is analyzed for the presence of hydrogen gas, which is given off by undigested lactose. A higher-than-average level shows lactose intolerance.
  • Test for acidity in the stool. For infants and children who are too young to do the hydrogen breath test properly, this test can show undigested lactose.
  • Blood tests that can evaluate for other diseases that can present with similar symptoms.
  • Upper endoscopy. During this test, your child is sedated, and their doctor passes a thin, flexible tube with a camera through their mouth and stomach to the small intestine. The doctor takes a small sample of tissue called a biopsy to be analyzed for the lactase enzyme.