Faecal calprotectin is a protein released by white blood cells into your gut, and its level in a stool sample reflects how much inflammation is present in the intestines. A result below 100 µg/g is generally treated as normal by most laboratories, while higher values suggest active inflammation that needs a closer look. It is one of the most useful non-invasive tests for telling inflammatory bowel disease apart from conditions like irritable bowel syndrome.
What is a faecal calprotectin test?
Calprotectin is a calcium- and zinc-binding protein found mainly inside neutrophils, a type of white blood cell. When the lining of the intestine becomes inflamed, these cells migrate into the gut wall and release calprotectin, which then passes into the stool. Because the protein is remarkably stable in faeces for several days at room temperature, it can be measured reliably from a small stool sample sent to the lab.
Doctors order a faecal calprotectin test to answer a very specific question: is there genuine inflammation in the bowel, or are the symptoms coming from a non-inflammatory cause? Persistent diarrhoea, abdominal pain, blood in the stool, unexplained weight loss or a change in bowel habit can all have overlapping causes. This stool test helps separate inflammatory bowel disease (IBD) — which includes Crohn's disease and ulcerative colitis — from irritable bowel syndrome (IBS), a functional disorder that does not cause measurable gut inflammation. It is also widely used to monitor people already diagnosed with IBD, because the level tends to rise before symptoms flare and fall when treatment is working. As a simple stool test, it often spares patients an unnecessary colonoscopy. It sits within the broader family of diagnostic lab tests your doctor may draw on to build a full picture.
Faecal calprotectin normal range
Faecal calprotectin is reported in micrograms of protein per gram of stool (µg/g). A value under 100 µg/g is generally regarded as normal and makes significant bowel inflammation unlikely. Results between roughly 100 and 200 µg/g fall in a borderline zone that often warrants a repeat test, and progressively higher values point to more active inflammation. The tier bands below reflect standard laboratory reference ranges used to grade a result.
| Faecal calprotectin (µg/g) | Interpretation |
|---|---|
| 0 – 100 | Normal — significant bowel inflammation unlikely |
| 101 – 200 | Borderline / mildly raised — often repeated or reviewed in context |
| 201 – 500 | Moderately raised — inflammation likely, further evaluation advised |
| 501 – 1000 | High — strongly suggests active inflammation |
| 1001 – 5000 | Very high — marked active inflammation |
It is worth knowing that laboratories report calprotectin in µg/g (sometimes written mg/kg, which is the same thing), and the exact cut-off used to call a result "raised" can vary from lab to lab and from one test kit to another. Always read your value against the reference range printed on your own report, and interpret it alongside your symptoms rather than in isolation. If you are tracking this marker over time, keeping your results in one place with ExaHealth makes it much easier to see whether inflammation is settling or climbing.
Normal range by age, sex and condition
The reference bands above are the general adult standard. Faecal calprotectin does not have separate validated numeric cut-offs for men versus women, but several real clinical factors can shift a result up or down, and a good clinician reads the number in the light of these. The table summarises the qualitative direction of those effects — the numbers themselves stay as printed on your report.
| Situation | Effect on calprotectin | Why |
|---|---|---|
| Infants and very young children | Naturally higher baseline | Healthy babies have higher gut calprotectin, so adult cut-offs do not apply and paediatric interpretation is different. |
| Older adults | May read higher | Age-related gut changes, diverticular disease and more frequent medication use can nudge levels up without IBD. |
| NSAID / painkiller users | Falsely raised | Aspirin, ibuprofen and similar anti-inflammatory drugs irritate the gut lining and can lift calprotectin. |
| Recent gut infection | Temporarily raised | Bacterial or viral gastroenteritis causes real, but transient, inflammation that resolves after recovery. |
| Pregnancy | Interpret with care | There are no distinct pregnancy cut-offs; results are read cautiously alongside symptoms. |
| Known IBD, on treatment | Used as a trend | The absolute band matters less than the direction — a falling number suggests treatment is controlling inflammation. |
Because these factors can all move the result, your doctor will usually ask about recent infections, painkiller use and your symptoms before deciding what a borderline value means. A single mildly raised reading is often repeated after a few weeks rather than acted on immediately.
What high faecal calprotectin means
A raised faecal calprotectin tells you there is inflammation in the intestine — it does not by itself name the cause. Above roughly 100 µg/g the likelihood of a genuinely inflammatory process rises, and values in the moderate-to-high bands (over 200–500 µg/g) make active inflammation increasingly likely. The commonest serious cause is inflammatory bowel disease: Crohn's disease, which can affect any part of the digestive tract, and ulcerative colitis, which affects the large bowel. In someone already diagnosed with IBD, a rising number is often an early sign of a flare, sometimes before symptoms return.
Inflammation is not always IBD, though. Gut infections (bacterial, viral or parasitic), regular use of NSAID painkillers, coeliac disease, diverticulitis, and in some cases colorectal polyps or cancer can all raise calprotectin. Typical symptoms that accompany a high result include ongoing diarrhoea, cramping abdominal pain, blood or mucus in the stool, urgency, fatigue and unintended weight loss. Because the causes range from self-limiting to serious, a high value usually leads to further tests — often stool cultures, blood tests, and a colonoscopy with biopsies to see and sample the bowel lining directly. If you are also having kidney or other systemic symptoms, your doctor may broaden the workup; our overview of kidney function tests explains one such panel.
What low faecal calprotectin means
A low or normal faecal calprotectin — under 100 µg/g — is a reassuring result. It means significant bowel inflammation is unlikely, and in someone with abdominal symptoms it points away from IBD and towards a functional cause such as irritable bowel syndrome. IBS is real and can be genuinely distressing, but it does not damage or inflame the gut wall, so calprotectin stays in the normal band. There is no such thing as a calprotectin that is "too low" — the test only tells you about the presence of inflammation, so a very low number is simply a normal number.
One caveat: a normal result does not completely rule out disease if it is inconsistent with a strong clinical picture. Inflammation that is patchy, very early, or limited to the small bowel can occasionally give a normal reading, which is why doctors interpret it together with symptoms, examination and other tests rather than treating a single normal value as the final word.
How to manage and improve your faecal calprotectin
Faecal calprotectin is a mirror of gut inflammation, so the way to bring it down is to address whatever is driving that inflammation — which means it is not something you can simply diet away on your own. The most important step is to get the underlying cause diagnosed and, if it is IBD, to stay on the treatment your gastroenterologist prescribes. When medication controls the disease, the number typically falls, and repeat testing is one of the clearest ways to confirm treatment is working.
Alongside medical care, some general measures support gut health and can help avoid falsely raised results. Where possible, limit regular use of NSAID painkillers such as ibuprofen and diclofenac, which are freely available across India but can irritate the gut lining — ask your doctor about alternatives if you use them often. Eat a varied, fibre-containing diet built around everyday Indian staples such as dals, seasonal vegetables, curd and whole grains, adjusting fibre to what your gut tolerates during a flare. Stay well hydrated, don't smoke (smoking worsens Crohn's disease), and manage stress, which can amplify gut symptoms even when inflammation is controlled.
When to see a doctor: seek medical advice for diarrhoea lasting more than a couple of weeks, blood or mucus in the stool, unexplained weight loss, persistent abdominal pain, or if a previously normal calprotectin starts rising. These warrant proper evaluation rather than self-treatment. Tracking your results over time — for instance with ExaHealth — helps you and your doctor spot a trend early. You may also find our explainers on related lab work useful, such as complement C3 and antinuclear antibodies, which are sometimes checked when inflammation is being investigated more broadly.
Guidelines and references
The tier bands in this article reflect standard laboratory reference ranges as used in ExaHealth's biomarker range data. Faecal calprotectin cut-offs vary by laboratory and assay, so always read your result against your own report. For general, authoritative background on gut health and inflammatory bowel disease, the following bodies are widely recognised:
Frequently asked questions
What is a normal faecal calprotectin level?
A faecal calprotectin under 100 µg/g is generally considered normal and makes significant bowel inflammation unlikely. Values between 101 and 200 µg/g are borderline and are often repeated, while higher results suggest more active inflammation.
Does a high calprotectin always mean I have IBD?
No. A high result shows inflammation in the gut but does not name the cause. Inflammatory bowel disease is one important cause, but infections, NSAID painkillers, coeliac disease and other conditions can also raise it, which is why further tests are usually done.
Can faecal calprotectin tell IBD apart from IBS?
It helps a great deal. Irritable bowel syndrome does not inflame the gut wall, so calprotectin typically stays normal, whereas inflammatory bowel disease usually raises it. A normal value in someone with gut symptoms points away from IBD and towards a functional cause like IBS.
What units are used for calprotectin, and why do cut-offs differ?
Calprotectin is reported in micrograms per gram of stool (µg/g), sometimes written as mg/kg, which is the same measure. The exact cut-off used to call a result raised varies between laboratories and test kits, so read your value against your own report's reference range.
What can falsely raise my calprotectin result?
NSAID painkillers such as ibuprofen and aspirin, a recent gut infection, and some other bowel conditions can lift calprotectin without IBD being present. Tell your doctor about recent illness or painkiller use so a borderline result can be interpreted correctly.
How is the stool sample collected for this test?
You collect a small sample of stool at home in the container the lab provides and return it for analysis. Calprotectin is stable in faeces for several days, so a single sample is usually enough; follow the specific instructions given by your laboratory.