How Doctors Diagnose Irritable Bowel Syndrome

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Doctor and patient exam
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Research studies estimate about 10 to 15% of U.S. adults have irritable bowel syndrome, or IBS. But only 5 to 7% have received a diagnosis. If your symptoms include pain in your abdomen and changes in your bowel movements, you may be among those who must cope with this condition.

Seeing your doctor is the first step down the path to diagnosis—and treatment to relieve your complaints. Your doctor will ask you questions about your health history, perform an exam, and may need to order some tests to rule out other conditions and confirm your diagnosis.

Taking Your Health History

First your doctor will ask you questions about your symptoms, as well as your medical past. Come prepared to discuss how you’re feeling, when you first noticed these signs, and whether you experienced a stressful life event recently. Your doctor may also want to know your family history of digestive disorders, as well as any recent infections or prescriptions you’ve had yourself.

Your answers help your doctor do a bit of medical detective work. He or she may diagnose you with IBS if:

  • Pain or discomfort strikes you in the abdomen at least three times a month—and has done so for three months.

  • You have had symptoms for more than six months.

  • Your pain or discomfort improves after a bowel movement, changes how often you go, or alters how your stool appears.

Performing a Physical Exam

Next, your doctor will examine your body for signs of IBS or other gastrointestinal disorders. He or she will check to see if your abdomen appears distended, or stretched out, and listen to how it sounds through a stethoscope. Finally, your doctor may tap or gently press on your abdomen to see if you feel tenderness or pain. 

Ordering Blood or Other Lab Tests 

No single lab test results in an IBS diagnosis. Your doctor may use clinical tests to rule out other causes for your symptoms. For instance, you may need to have:

  • Lower GI (gastrointestinal) series, which is an X-ray of your large intestine

  • Stool test, which checks for blood or parasites

  • Blood tests for celiac disease, a digestive disorder in which the small intestine is damaged by an abnormal immune response to gluten. Some of the symptoms, such as belly pain, are the same as those for IBS.

  • Flexible sigmoidoscopy or colonoscopy. These tests allow doctors to see inside your lower gastrointestinal tract. If growths (called polyps) are present, your doctor will take a small sample of tissue (called a biopsy) to check for colon cancer. Though IBS is not linked to colon cancer, some of the same symptoms occur in both conditions.

Once you receive an IBS diagnosis, you and your doctor can work on the best way to manage your condition. Changing your diet to avoid gas-producing foods, carbonated drinks, and artificial sweeteners may help. So might stress relief, relaxation techniques, peppermint oil, and medications.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 May 10
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

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