Health professionals usually begin testing the causes of gas in the digestive tract with a review of dietary habits and symptoms. If the gas is accompanied by other symptoms, like unexpected weight loss, chest pain, or blood in the digestive tract, it may indicate a serious problem. Otherwise, the health professional may ask the patient to keep a diary of foods and beverages consumed for a specific period.
If lactase deficiency is the suspected cause of gas, the health professional may suggest avoiding milk products for some time. A blood or breath test may be used to diagnose lactose intolerance. A blood test may also be done if there is reason to suspect celiac disease.
To determine if someone produces too much gas in the colon or is unusually sensitive to the passage of normal gas volumes, the health professional may ask a patient to count the number of times he or she passes gas during the day and include this information in a diary.
Careful review of diet and the amount of gas passed may help relate specific foods to symptoms and determine the severity of the problem. If a particular food seems to cause the problem, the doctor may suggest cutting it out of the diet to see if the condition improves.
Since the symptoms that people have are so variable, the health professional may order other types of diagnostic tests in addition to a physical exam, depending on the patient''s symptoms and other factors.