Stomach pain, diarrhea and bloating can happen with both irritable bowel syndrome (IBS) and celiac disease, so it is common to wonder which one fits best. The main difference is that IBS is a disorder of gut function, while celiac disease is an immune reaction to gluten that can damage the small intestine. Because the symptoms overlap, rule-out testing can be an important step, especially before someone assumes symptoms are “just IBS” or starts avoiding gluten.
Why celiac disease can look like IBS
When comparing celiac vs IBS, the symptom list can feel almost identical: cramping, changes in bowel habits, gas, diarrhea and bloating. Celiac disease can also come and go, which adds to confusion. What often separates celiac disease from IBS is the risk of malabsorption (trouble absorbing nutrients). Over time, celiac-related inflammation can interfere with nutrient absorption and lead to signs like unintended weight loss, iron-deficiency anemia, low bone density, and ongoing fatigue.
This overlap is the reason many guidelines encourage celiac testing when IBS symptoms include diarrhea. The American College of Gastroenterology (ACG) recommends serologic (blood) testing to rule out celiac disease in people with IBS and diarrhea symptoms, because celiac disease is an important and treatable condition that can hide under an IBS label. [1]
It also helps to separate gluten intolerance vs IBS in conversation. “Gluten intolerance” is often used to describe symptoms related to gluten without celiac disease, but unlike celiac disease, there is no single blood test that can confirm non-celiac gluten sensitivity. That is why celiac disease (and sometimes wheat allergy) is usually ruled out first.
When to test and what the testing usually includes
A “celiac test for IBS symptoms” often makes the most sense when symptoms include frequent loose stools or when there are clues that suggest malabsorption. Common reasons clinicians consider testing include:
- Ongoing diarrhea and bloating
- Unexplained weight loss
- Unexplained iron-deficiency anemia
- Low bone density (osteopenia or osteoporosis)
- Celiac disease in a close family member or certain autoimmune conditions
Guideline summaries also note that celiac testing should be considered in people with unexplained diarrhea, weight loss, abdominal pain, or bloating, and in some people with other unexplained findings (like iron deficiency). [2]
The most commonly used first blood test is tissue transglutaminase immunoglobulin A (tTG-IgA) (often written as tTG IgA). Because some people have immunoglobulin A (IgA) deficiency, clinicians often check a total IgA level as well. If IgA is low, IgG-based tests may be used instead. [3] If blood tests suggest celiac disease, diagnosis is usually confirmed with an upper endoscopy and small intestine biopsies.
One key testing detail matters: do not stop eating gluten before testing unless a clinician has advised it. Going gluten-free can cause antibody levels to drop and may make results look normal even when celiac disease is present. [4]
For tracking and follow-up, consider saving celiac-related labs and procedure results (bloodwork and biopsy reports) in Aidy, so they are easy to find and share across appointments.