IBS specialist tests overview

Overview

Irritable bowel syndrome (IBS) is a common condition that affects the large intestine. It causes symptoms like stomach pain, bloating, and changes in bowel habits (diarrhea or constipation). IBS does not damage the bowel, but it can be uncomfortable and affect your quality of life. Doctors diagnose IBS mainly by ruling out other conditions, so specialist tests help make sure nothing else is causing your symptoms.

Yes, IBS is very common. It affects about 1 in 20 people in the UK at some point in their lives. It is one of the most common reasons people see a gastroenterologist (a specialist in digestive health).

IBS can affect people of any age, but it most often starts in teenage years or early adulthood. Women are about twice as likely to have IBS as men. It can also run in families.

Symptoms

Common symptoms

• Stomach pain or cramping that often improves after a bowel movement
• Bloating and excess gas
• Diarrhoea, constipation, or alternating between the two
• A feeling that you haven't finished a bowel movement
• Passing mucus from the back passage

Symptoms in children

• Stomach pain that comes and goes, often around the belly button
• Changes in bowel habits (diarrhoea or constipation)
• Feeling sick or bloated
• Symptoms may be worse with stress or certain foods

Symptoms in older adults

• Same core symptoms as younger adults, but may also have unintended weight loss or anaemia (low iron), which should be checked promptly
• Constipation can become more common
• Symptoms may be mistaken for other age-related digestive issues

Causes

Main causes

• The exact cause is not known, but it involves problems with how the gut moves food (motility) and increased sensitivity of the bowel
• Communication problems between the brain and the gut (the 'gut-brain axis')
• Changes in the normal bacteria in the gut (gut microbiome)
• Triggers like certain foods, stress, or infections

Risk factors

• Being female
• Having a family history of IBS
• Experiencing stressful life events or having anxiety or depression
• Having had a severe gut infection such as gastroenteritis
• Food intolerances or sensitivities

When to see a doctor

See a doctor urgently if:

• If you have any blood in your stool (bright red or dark red)
• If you have unexplained weight loss
• If you are over 50 and have a change in bowel habit lasting more than 6 weeks

Book a routine appointment if:

• If you have persistent stomach pain, bloating, or changes in bowel habits that last more than a few weeks
• If symptoms are affecting your daily life or sleep
• If you have tried simple self-care measures and they haven't helped

Diagnosis

IBS is usually diagnosed based on your symptoms and by checking for other possible causes. Your doctor will ask about your symptoms, do a physical exam, and may recommend some tests to rule out conditions like coeliac disease or inflammatory bowel disease. The diagnosis of IBS is often made if you have had symptoms for at least 6 months and meet certain criteria (like the Rome IV criteria).

Tests that may be done

• Blood tests: to check for inflammation, anaemia, or coeliac disease
• Stool tests: to look for blood, infection, or signs of inflammation
• Breath tests: to check for lactose intolerance or bacterial overgrowth in the small bowel
• Ultrasound: to look at your abdomen and rule out other problems
• Colonoscopy or sigmoidoscopy: a camera test to look inside your bowel, usually only if you have red flag symptoms like blood or unexplained weight loss

What to expect at your appointment

Tests are usually done as an outpatient. They are generally quick and not painful, though some may cause mild discomfort. Your doctor will explain each test and what to do to prepare, for example, a special diet before a breath test or a laxative before a colonoscopy. Results may take from a few days to a few weeks. You will have a follow-up appointment to discuss the results and your diagnosis.

Treatment

Treatment for IBS focuses on managing symptoms and improving quality of life. There is no cure, but many people find relief with a combination of lifestyle changes, dietary adjustments, stress management, and sometimes medications. Treatment plans are individualised and may need to be adjusted over time.

Self-care at home

• Keep a food and symptom diary to identify triggers
• Eat regular meals and avoid skipping meals
• Try a low-FODMAP diet under guidance of a dietitian
• Drink plenty of water, especially for constipation
• Manage stress with relaxation techniques, exercise, or talking therapy
• Get enough sleep and stay physically active

Medical treatments

Depending on your main symptoms (e.g., pain, diarrhoea, or constipation), your doctor may suggest therapies such as fibre supplements, laxatives or anti-diarrhoea medicines (available over the counter or on prescription). They may also recommend medications that affect how the bowel moves or how the brain processes pain signals. Always follow your doctor's advice and do not self-prescribe.

When is surgery considered?

Surgery is not a treatment for IBS. However, if tests find another condition (e.g., gallstones or a blocked bowel), surgery may be needed for that condition, not for IBS itself.

Living with this condition

Living with IBS can be challenging, but many people learn to manage their symptoms well. It helps to have a routine for meals, exercise, and sleep. Planning ahead for travel and social events can reduce anxiety. Keep a symptom diary to spot patterns and talk openly with your doctor about any changes.

Lifestyle tips

• Regular physical activity like walking or swimming can improve bowel function and reduce stress
• Practice relaxation or mindfulness to calm the gut-brain connection
• Avoid smoking and limit alcohol and caffeine if they seem to worsen symptoms

Diet and exercise

A balanced diet with plenty of fibre from fruits, vegetables, and whole grains is helpful, but you may need to adjust types of fibre (soluble vs insoluble) depending on your symptoms. The low-FODMAP diet is often recommended, but only for a short time with help from a dietitian. Regular exercise, such as 30 minutes most days, can ease symptoms and improve overall health.

Mental health and emotional wellbeing

IBS is closely linked to stress and anxiety. The condition itself can cause worry, which can make symptoms worse. This cycle can be broken with relaxation techniques, cognitive behavioural therapy (CBT), or talking to a counsellor. It's important to address the emotional side of IBS, not just the physical symptoms.

Prevention

There is no sure way to prevent IBS, but you may reduce the risk of flare-ups by managing stress, eating a healthy diet, and staying active. Avoiding known triggers and treating gut infections promptly may also help.

Vaccines

No vaccine is available for IBS.

Screening programmes

There is no routine screening test for IBS. However, if you have a family history of bowel cancer or other bowel conditions, your doctor may recommend screening (such as a colonoscopy) regardless of IBS symptoms.

Complications

If left untreated

• Chronic pain and discomfort that can affect daily life
• Poor quality of sleep and fatigue
• Anxiety or depression due to ongoing symptoms
• Nutritional deficiencies if you avoid many foods unnecessarily

Long-term outlook

Most people with IBS can manage their symptoms well with the right support. The condition does not damage the bowel or increase the risk of cancer. With lifestyle changes, dietary adjustments, and sometimes medication, many people achieve a good quality of life. Symptoms can come and go, but they often improve over time.

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