Irritable bowel syndrome (IBS)
A very common long-term disorder of how the gut works, causing abdominal pain with bloating and altered bowel habits, without any damage or disease visible in the bowel. It is diagnosed on the symptom pattern once other conditions are excluded, and managed rather than cured.
What it is
Irritable bowel syndrome is a functional gut disorder — the bowel is structurally normal, but the way it works and communicates with the brain is disturbed, causing real and often distressing symptoms. It is one of the commonest conditions seen in general practice, affecting women more than men, and typically features recurrent abdominal pain linked to going to the toilet, along with bloating and a change in bowel habit — some people have predominant diarrhoea, some constipation, and some alternate between the two. Symptoms are often triggered by certain foods, stress and hormonal changes. Crucially, IBS does not damage the bowel or lead to cancer, and routine tests are normal — which is both reassuring and the reason it is partly a diagnosis of exclusion: the main job of investigation is to confidently rule out conditions that can look similar, especially coeliac disease and inflammatory bowel disease, before settling on IBS. It is diagnosed using symptom-based criteria plus a few targeted tests, and managed with diet, lifestyle and symptom-directed treatments.
Key lab markers
- Full blood count, CRP and ESR — normal in IBS; raised inflammatory markers or anaemia point away from IBS toward inflammatory bowel disease.
- Coeliac serology (anti-tTG with total IgA) — to exclude coeliac disease, which can mimic IBS.
- Ferritin — iron deficiency is a red flag against a simple IBS diagnosis.
- Faecal calprotectin — a stool test that helps separate IBS (normal) from inflammatory bowel disease (raised).
- Colonoscopy — reserved for alarm features (weight loss, bleeding, anaemia, age over 50, family history). Normal results support IBS; the tests are chosen to exclude mimics, not to 'prove' IBS.
Symptoms
- Recurrent abdominal pain or cramping, often relieved by opening the bowels
- Bloating and a distended tummy
- A change in bowel habit — diarrhoea, constipation, or alternating
- A feeling of incomplete emptying, or urgency
- Mucus in the stool
- Symptoms triggered by certain foods, stress or the menstrual cycle
- Symptoms that come and go over months to years, without weight loss or bleeding
Related symptoms
Related lab panels
When to discuss with a doctor
IBS is diagnosed when typical symptoms are present and a few targeted tests (to exclude coeliac disease and inflammatory bowel disease) are normal; it does not usually need extensive investigation. See a doctor to make the diagnosis confidently and to start management — which can be very effective — including dietary approaches (such as a low-FODMAP diet with guidance), fibre adjustment, stress management, and medicines aimed at the main symptom. Importantly, certain 'alarm' features are NOT typical of IBS and warrant fuller investigation: unintentional weight loss, bleeding from the bottom or black stools, a change in bowel habit over the age of 50, anaemia, a family history of bowel cancer or inflammatory bowel disease, or waking at night with symptoms. Mediora.AI can show that inflammatory and coeliac markers are normal, supporting IBS over its mimics; the diagnosis and management belong with your doctor.