digestive disorders
Lactose Intolerance
Diagnosis of Lactose Intolerance
A doctor's evaluation of symptoms that occur after consuming lactose Sometimes a hydrogen breath test A doctor suspects lactose intolerance when a person has symptoms after consuming dairy products. If a 3- to 4-week trial period of a diet free of dairy products eliminates the symptoms, and symptoms then return when the person consumes dairy products, the diagnosis is confirmed. Specific tests are rarely necessary, but in some people, doctors confirm the diagnosis with a breath test. Thehydrogen breath test(also called a lactose breath test) is a 4-hour test. For this test, people consume a small, measured amount of lactose. Before and after consuming the lactose, doctors measure the amount of hydrogen gas in the person's breath at 1-hour intervals. They measure hydrogen because intestinal bacteria produce hydrogen when they digest unabsorbed lactose. If the amount of hydrogen in the breath rises significantly after consuming lactose, then the person is lactose intolerant. Thelactose tolerance testis an alternative, less sensitive test that is now rarely done. After people consume a measured amount of lactose, doctors monitor their symptoms and measure their blood sugar (glucose) levels several times. People who can digest lactose develop no symptoms and their blood glucose level rises. People who cannot digest lactose develop diarrhea, abdominal bloating, and discomfort within 20 to 30 minutes and their blood glucose level does not rise. 