There are no specific tests for IBS. Many cases can be diagnosed based on your symptom history and your GP will undertake some routine blood and stool tests to rule out other conditions. As the symptoms of IBS are similar to other conditions such as coeliac disease and inflammatory bowel disease, it is important to rule these out. It is important not to make any dietary changes until these tests have been done. This is particularly important for the blood test for coeliac disease as the result can be affected by your diet. Private allergy testing (for example hair sampling) is not a reliable way to test for allergies or intolerances. If you are concerned, please talk to your GP.