How to diagnose Lactose Intolerance ?
A health care provider makes a diagnosis of lactose intolerance based on
                
- medical, family, and diet history, including a review of symptoms  - a physical exam  - medical tests
                
Medical, family, and diet history. A health care provider will take a medical, family, and diet history to help diagnose lactose intolerance. During this discussion, the health care provider will review a patients symptoms. However, basing a diagnosis on symptoms alone may be misleading because digestive symptoms can occur for many reasons other than lactose intolerance. For example, other conditions such as irritable bowel syndrome, celiac disease, inflammatory bowel disease, or small bowel bacterial overgrowth can cause digestive symptoms.
                
Physical exam. A physical exam may help diagnose lactose intolerance or rule out other conditions that cause digestive symptoms. During a physical exam, a health care provider usually
                
- checks for abdominal bloating  - uses a stethoscope to listen to sounds within the abdomen  - taps on the abdomen to check for tenderness or pain
                
A health care provider may recommend eliminating all milk and milk products from a persons diet for a short time to see if the symptoms resolve. Symptoms that go away when a person eliminates lactose from his or her diet may confirm the diagnosis of lactose intolerance.
                
Medical tests. A health care provider may order special tests to provide more information. Health care providers commonly use two tests to measure how well a person digests lactose:
                
- Hydrogen breath test. This test measures the amount of hydrogen in a persons breath. Normally, only a small amount of hydrogen is detectable in the breath when a person eats or drinks and digests lactose. However, undigested lactose produces high levels of hydrogen. For this test, the patient drinks a beverage that contains a known amount of lactose. A health care provider asks the patient to breathe into a balloon-type container that measures breath hydrogen level. In most cases, a health care provider performs this test at a hospital, on an outpatient basis. Smoking and some foods and medications may affect the accuracy of the results. A health care provider will tell the patient what foods or medications to avoid before the test.  - Stool acidity test. Undigested lactose creates lactic acid and other fatty acids that a stool acidity test can detect in a stool sample. Health care providers sometimes use this test to check acidity in the stools of infants and young children. A child may also have glucose in his or her stool as a result of undigested lactose. The health care provider will give the childs parent or caretaker a container for collecting the stool specimen. The parent or caretaker returns the sample to the health care provider, who sends it to a lab for analysis.