Calprotectin stool test: what the result means
- Updated
- 2026-09-10
- Every number with its source
What calprotectin is
Calprotectin is a protein found in neutrophils — one of the types of white blood cells. When inflammation is going on in the lining of the intestine, neutrophils are drawn to that spot in greater numbers and some of them end up in the intestinal contents, so the amount of calprotectin in stool goes up. This test is used to tell apart two conditions whose symptoms can be very similar but whose treatment differs fundamentally. One of them is inflammatory bowel disease (Crohn's disease or ulcerative colitis), where inflammation really is going on in the intestinal wall; the other is irritable bowel syndrome, where the symptoms (abdominal pain, diarrhoea, bloating) are there but there is no inflammation. A normal or low amount of calprotectin usually means the intestine is not inflamed, and the symptoms are most likely caused by a non-inflammatory cause. A raised amount indicates inflammation, but it does not say what is causing it — further tests are needed for that, most often a colonoscopy.
How the result is reported
The MedlinePlus page does not give numeric reference limits with units for calprotectin — the cut-off depends on the laboratory's method. You will find the exact reference interval with units (µg/g) for your own result on your laboratory report. A raised amount shows that there is inflammation, but not what is causing it; the exact cause is established by a doctor from further tests.
| Result | What it is most often associated with per MedlinePlus | What to keep in mind |
|---|---|---|
| Markedly raised | Inflammatory bowel disease or a bacterial intestinal infection | A raised amount indicates inflammation but does not say its cause — further tests are needed for that, most often a colonoscopy |
| Moderately raised | May indicate intestinal or colon cancer, celiac disease, certain bacterial infections (for example C. difficile), treated inflammatory bowel disease, or be linked to the use of non-steroidal anti-inflammatory drugs (NSAIDs) | One of the things a doctor checks is whether NSAIDs, which can affect the result, are being taken |
| Normal or low | Usually means the intestine is not inflamed | The symptoms are then most likely caused by a non-inflammatory condition, for example irritable bowel syndrome |
When the test is done
- When there is chronic diarrhoea, abdominal pain or bloating and the aim is to tell whether the cause is inflammatory (IBD) or non-inflammatory (irritable bowel syndrome)
- When blood, mucus or pus is noticed in the stool
- When weight drops unexpectedly with no clear reason
- Once Crohn's disease or ulcerative colitis has been diagnosed — to monitor how active the inflammation is and how well treatment is working
- When a doctor is considering whether a colonoscopy is needed to establish the cause of the symptoms
How to prepare
- Ask your doctor whether any medicines need to be stopped before the test — especially non-steroidal anti-inflammatory drugs (NSAIDs)
- The test needs a stool sample — your doctor or the laboratory will explain how to collect and deliver it properly
A raised calprotectin
A markedly raised calprotectin, per MedlinePlus, is most often associated with inflammatory bowel disease or a bacterial intestinal infection. A moderately raised amount may indicate intestinal or colon cancer, celiac disease, certain bacterial infections (for example C. difficile), treated inflammatory bowel disease, or be linked to the use of non-steroidal anti-inflammatory drugs (NSAIDs).
Possible causes of a raised result
- Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
- A bacterial intestinal infection causing food poisoning
- Intestinal or colon cancer
- Celiac disease
- Certain bacterial infections in the intestine (for example Clostridium difficile)
- The use of non-steroidal anti-inflammatory drugs (NSAIDs)
- Inflammatory bowel disease that has already been treated but is still active
Symptoms that can accompany a raised result
- Severe watery or bloody diarrhoea
- Abdominal pain
- Cramping spasms
- Blood, mucus and/or pus in the stool
- Unexpected weight loss
What to discuss with a doctor after a raised result
- Whether the symptoms and the result fit the signs of inflammatory bowel disease, and whether a colonoscopy is needed to clarify the cause
- Whether non-steroidal anti-inflammatory drugs (NSAIDs), which can affect the result, are being taken
- Which other tests (blood, endoscopic) would help to tell the possible causes apart
- If the disease has already been diagnosed — whether the result shows that treatment is working
A normal or low calprotectin
A normal or low amount of calprotectin, per MedlinePlus, usually means the intestine is not inflamed. In that case the symptoms (abdominal pain, diarrhoea, bloating) are most likely caused by a non-inflammatory condition, for example irritable bowel syndrome, rather than by inflammatory bowel disease.
What can lie behind a normal or low result
- There is no inflammation in the intestine — a normal state
- The symptoms are caused by a non-inflammatory cause, for example irritable bowel syndrome
What to discuss with a doctor after a normal result
- Whether irritable bowel syndrome or another non-inflammatory cause can explain the symptoms
- Whether further tests are needed if the symptoms persist despite a normal result
Calprotectin and colonoscopy
The calprotectin test is a non-invasive stool test that helps decide whether a colonoscopy is needed at all. If calprotectin is raised, a doctor most often orders a colonoscopy to assess the intestine directly and to establish the cause of the inflammation.
Related pages
Related pages on this site: CRP, hs-CRP, ferritin and haemoglobin.
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal calprotectin level?
The MedlinePlus page of the US National Library of Medicine does not give a specific numeric reference value with units — the cut-off depends on the laboratory's method. You will find the exact reference interval with units (µg/g) for your own result on your laboratory report.
›What is a calprotectin stool test used for?
The test is used to check whether there is inflammation in the intestine, and it helps tell inflammatory bowel disease (Crohn's disease, ulcerative colitis) from irritable bowel syndrome, where the symptoms are similar but there is no inflammation (MedlinePlus).
›What does a raised calprotectin mean?
A markedly raised amount is most often associated with inflammatory bowel disease or a bacterial infection. A moderate rise may be linked to celiac disease, certain bacterial infections, intestinal cancer or the use of non-steroidal anti-inflammatory drugs (MedlinePlus). The exact cause is established by a doctor from further tests.
›What does a low or normal calprotectin mean?
A normal or low amount of calprotectin usually means the intestine is not inflamed, and the symptoms are most likely caused by a non-inflammatory cause, for example irritable bowel syndrome (MedlinePlus).
›Is there anything to avoid before the test?
MedlinePlus recommends asking your doctor whether any medicines need to be stopped before the test, especially non-steroidal anti-inflammatory drugs (NSAIDs), because they can affect the result.
›How does a calprotectin test differ from a colonoscopy?
The calprotectin test is a non-invasive stool test that helps decide whether a colonoscopy is needed at all. If calprotectin is raised, a doctor most often orders a colonoscopy to assess the intestine directly and to establish the cause of the inflammation.
Sources
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.