Faecal Calprotectin Test: How It Helps Tell IBS From Inflammatory Bowel Disease

Tummy pain, bloating and diarrhoea can be caused by irritable bowel syndrome or by inflammatory bowel disease. A simple stool test called faecal calprotectin helps tell them apart and can save many people from an unnecessary colonoscopy.

Imagine months of loose stools and cramping. You worry it is something serious, but you dread a camera test. Your healthcare provider sends you home with a small pot, and a week later a normal calprotectin result points towards IBS.

What calprotectin is

Calprotectin is a protein released by white blood cells called neutrophils. When the lining of the bowel is inflamed, neutrophils move into the bowel and calprotectin levels in the stool rise.,Measuring calprotectin in a stool sample gives a good indication of whether there is inflammation in the gut.

Why the test is used

• To help distinguish inflammatory bowel disease (Crohn’s disease and ulcerative colitis) from irritable bowel syndrome in adults with new lower gut symptoms
• To decide who needs a colonoscopy
• To monitor people with known inflammatory bowel disease
• To check whether a flare is likely

IBS vs IBD: why it matters

Irritable bowel syndrome (IBS) is very common and causes symptoms like pain, bloating and changes in bowel habit, but there is no inflammation or damage to the bowel. It is managed with diet, lifestyle changes and medicines.,Inflammatory bowel disease (IBD) involves real inflammation that can damage the bowel and needs specialist treatment. Getting the diagnosis right means the right treatment and avoids unnecessary tests or worry.

How to collect a sample

1. Use the container and instructions provided
2. Catch your stool on clean toilet paper, a disposable container or a special collection sheet so it does not touch toilet water
3. Use the scoop in the lid to collect a small sample
4. Close the lid tightly, label it and return it as instructed, usually within a day or two
5. Wash your hands thoroughly

Understanding results

Cut-offs vary between laboratories, but as a rough guide, a result below about 50 micrograms per gram (µg/g) is usually considered normal and makes IBD unlikely. Results between about 50 and 200 µg/g are borderline, and the test is often repeated. Results above about 200 µg/g suggest inflammation, and referral for further tests, such as a colonoscopy, is usually recommended.,Your healthcare provider will interpret your result alongside your symptoms, blood tests and age.

Other things that can raise calprotectin

• Gut infections
• Anti-inflammatory painkillers such as ibuprofen
• Some acid-reducing medicines (PPIs)
• Bowel cancer and polyps
• Coeliac disease and diverticular disease
• Tell your healthcare provider about any recent infection or medicines

Red flag symptoms

A normal calprotectin does not rule out other serious conditions. Always see a healthcare provider promptly if you have blood in your stool, unexplained weight loss, a change in bowel habit after age 50, a family history of bowel cancer, anaemia, or symptoms that wake you at night.

What happens next

If your result is normal and you have no red flags, your healthcare provider may diagnose IBS and suggest treatments such as dietary changes, fibre adjustments, peppermint oil, antispasmodics or a low-FODMAP diet with dietitian support. If your result is raised, you may be referred to a gastroenterologist for further tests.

Inflammatory bowel disease in more detail

Crohn’s disease can affect any part of the gut from the mouth to the anus, often in patches, and can involve the full thickness of the bowel wall. Ulcerative colitis affects only the large bowel and rectum, starting at the rectum and spreading upwards in a continuous pattern.

Both conditions often start in teenagers and young adults, though they can begin at any age. Symptoms include diarrhoea, sometimes with blood or mucus, urgency, tummy pain, weight loss, tiredness and sometimes joint pain, mouth ulcers, skin rashes or eye inflammation. Treatments include anti-inflammatory medicines, immune-suppressing medicines, biologic therapies and sometimes surgery.

Living with IBS

IBS is a long-term condition, but symptoms often improve with the right approach. Many people find it helps to eat regular meals, avoid large or very fatty meals, adjust fibre intake, limit caffeine, alcohol and fizzy drinks, and keep a food and symptom diary to spot triggers.

Stress and anxiety can make IBS worse, because the gut and brain are closely linked. Talking therapies, such as cognitive behavioural therapy or gut-directed hypnotherapy, have good evidence for IBS. A low-FODMAP diet can help many people, but it should be done with support from a dietitian, because it is restrictive and only meant to be followed strictly for a few weeks.

Calprotectin in people with IBD

For people already diagnosed with IBD, calprotectin is a useful way to monitor the condition without repeated colonoscopies. A rising level may suggest a flare is starting, even before symptoms appear, allowing treatment to be adjusted early. Your IBD team may ask for regular samples, especially after starting or changing treatment.

Questions to ask about your result

• What was my calprotectin level, and what is the laboratory’s normal range?
• Could a recent infection or medicine have affected it?
• Do I need a repeat test or a referral?
• If it is normal, what treatment do you recommend for my symptoms?
• Which symptoms should make me come back sooner?

Frequently asked questions

Is calprotectin used in children?

Yes, but normal levels are higher in young children, so results are interpreted differently.

Do I need to stop medicines before the test?

Ask your healthcare provider. Some may advise stopping anti-inflammatory painkillers beforehand.

How long do results take?

Usually one to two weeks.

Can stress raise calprotectin?

Stress can worsen gut symptoms, but it does not usually raise calprotectin significantly.

But what if my result is borderline?

Borderline results are common. Your healthcare provider may repeat the test in a few weeks, especially if you have recently had an infection or taken ibuprofen.

Related: IBS symptoms and diet · Colonoscopy

Sources: National Institute for Health and Care Excellence (DG11), British Society of Gastroenterology, Crohn’s and Colitis UK, American Gastroenterological Association.