- 1). Diagnosis of a gluten allergy may take weeks or longer because symptoms mimic common conditions such as IBS (irritable bowel syndrome). A visit to your doctor is the first step toward obtaining a diagnosis.
- 2). Performing various food-allergy tests is the first step that many doctors will take. This takes time. He or she may also prescribe anti-diarrhea medications, but be extra careful not to allow yourself to become dehydrated.
- 3). Undergoing an upper GI endoscopy is often the only definitive method to diagnose a gluten allergy, but this test is quite expensive.
- 4). Ask your doctor about gluten-allergy specific tests that may be run on blood-draw samples. However, be advised that such tests will have to be given twice---once when eating a normal diet and then again after eating a gluten-free diet.
Source...