Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder characterized by symptoms such as abdominal pain, bloating, and changes in bowel habits without any apparent structural or biochemical abnormalities. Diagnosing IBS is typically done based on a clinical evaluation of symptoms and by ruling out other potential conditions. In this article, we will dive into what lab tests diagnose IBS.

There isn’t a specific lab test that definitively diagnoses IBS. However, healthcare providers may order certain tests to rule out other conditions that could be causing similar symptoms. These tests may include:

  1. Blood tests: These can help identify conditions such as celiac disease, inflammatory bowel disease (IBD), and anemia.
  2. Stool tests: These tests may be done to check for infections, parasites, or other abnormalities in the stool.
  3. Colonoscopy or sigmoidoscopy: These procedures involve the examination of the colon or lower part of the bowel using a flexible tube with a camera. They can help identify conditions such as inflammatory bowel disease or colorectal cancer.
  4. Imaging studies: In some cases, imaging studies such as abdominal CT scans or MRIs may be ordered to rule out structural abnormalities in the digestive tract.

It’s important to note that there is no specific biomarker or definitive test for IBS. Diagnosis is often based on meeting specific criteria known as the Rome criteria, which include the presence of specific symptoms and the absence of alarm features (such as weight loss or blood in the stool) that might indicate a more serious condition.

If you have any questions about what lab tests diagnose IBS (or not), taking to a health care professional like a naturopathic doctor can help provide clarity around your health concerns. They can perform a thorough evaluation, consider your medical history, and order relevant tests to ensure an accurate diagnosis and appropriate management plan.


Book an appointment here with Dr. Liz Dalglish, ND, who focuses part of her practice in digestive health including IBS, chronic constipation and more!