It’s possible you have lactose intolerance if your symptoms improve dramatically when you avoid lactose. A trial period of 2 weeks for a lactose-free diet is usually all that is needed to make the diagnosis of lactose intolerance. In some cases, your doctor will want to do tests to confirm the diagnosis.
First of all your doctor will ask about symptoms, family and your medical history, and eating habits, then he will perform a physical exam and tests to help diagnose lactose intolerance or to check for other health problems. Health problems, such as irritable bowel syndrome, celiac disease, inflammatory bowel disease, or small bowel bacterial overgrowth can be the cause of symptoms similar to lactose intolerance.
During a physical exam, your doctor may
- check for bloating in your abdomen
- use a stethoscope to listen to sounds within your abdomen
- tap on your abdomen to check for tenderness or pain
What tests do doctors use to diagnose lactose intolerance?
A significant number of people having symptoms that suggest lactose intolerance will have normal results on all diagnostic tests. Similar symptoms (but normal results on the tests) can be caused by fructose, sorbitol or other sugars that are not easily digested in the small intestine. Similar symptoms can also result from irritable bowel syndrome.
And still there are 3 ways to diagnose lactose intolerance, they are:
- Hydrogen or Lactose breath test
- Stool Acidity Test
- Lactose Tolerance Test
Your doctor may order a hydrogen breath test to see how well your small intestine digests lactose.
Hydrogen or Lactose breath test
Doctors use this test to diagnose lactose malabsorption and lactose intolerance. Normally, we have a small amount of gas found in your breath called hydrogen. If you have lactose intolerance, undigested lactose is the reason you have high levels of hydrogen.
This test is very accurate. For this test, the patient drinks a lactose-loaded drink. Every 30 minutes over a few hours, your breathe will be tested by breathing into a balloon-type container. During this time, a HCP will ask about your symptoms. If both your breath hydrogen levels rise and your symptoms get worse during the test, your doctor may diagnose lactose intolerance. This kind of test can be given to to older children as well as adults. You cannot eat food for several hours beforehand, take medications and smoking that can change the test’s accuracy and you will need to skip them before the test.
This test is not given to young children and infants, because giving these kind of patients a lactose load will result in diarrhea (loose stool), which likely cause dehydration.
Stool Tool Acidity Test
Unlike hydrogen/lactose breath test this one can be used on infants and young children. This is an easy test which measures the amount of acid in childrens stools. Bear in mind that this test is not very accurate and specific
Lactose Tolerance Test
This kind of testing is used mainly when lactose breath test can’t be used for some reason. It is based on taking your deoxygenated blood with repeating the process after patient drink a large amount of a liquid that has lactose. Blood samples are taken over a two-hour period, which tell how well the body is able to digest lactose. This kind of test can be given to older children as well as adults. You will need to fast before this test. You will be diagnosed with lactose intolerance if your blood sugar levels do not change during this test, because this shows that the lactose was not digested in the normal way.