A doctor may recommend a lactose-tolerance test if you suspect a problem digesting lactose from dairy products.
Symptoms of lactose intolerance may include abdominal pain, bloating, gas and diarrhea.
The test involves collecting a series of breath samples exhaled into a collector, or a series of blood samples drawn from your arm.
A hydrogen breath test is the most common procedure, the American Association for Clinical Chemistry says. Breath levels of hydrogen increase after you are given a lactose-loaded drink. If the samples have high amounts of hydrogen, it is likely that you are lactose-intolerant.
A second procedure, a glucose blood test, evaluates whether blood-sugar levels increase with the consumption of lactose. If there is not a significant increase and a person has symptoms described above, it’s probably due to lactose intolerance.
Care must be taken when interpreting results of this test in people with diabetes, the association warns.