Urgent Official Appointment Info
English

Type the name of a condition or procedure, or a complaint. For example: reflux, colonoscopy, heartburn.

A Raised Faecal Calprotectin: What Does It Mean?

Also known as: Raised faecal calprotectin · High calprotectin in stool · Calprotectin test · Why does calprotectin rise? · What should calprotectin be?

Faecal calprotectin is a test that helps assess whether there is an inflammatory process in the bowel. A raised level is not on its own a diagnosis of Crohn’s disease or ulcerative colitis.

Prof. Ali Tüzün İnce, MD Last updated 6 min read

Faecal calprotectin is a laboratory test that helps assess whether there is an inflammatory process in the bowel.

A high result often leads people to worry: “Have I got Crohn’s disease?” or “Is this ulcerative colitis?” But:

A raised faecal calprotectin is not on its own a diagnosis of Crohn’s disease or ulcerative colitis.

Calprotectin can rise when there is inflammation in the bowel; but it does not on its own show what is causing that inflammation.

What is calprotectin?

Calprotectin is a protein found in particular abundance in the inflammatory cells called neutrophils.

When inflammation develops in the bowel lining, neutrophils pass into the bowel and the amount of calprotectin in the stool can rise. This makes faecal calprotectin a non-invasive biomarker used to assess inflammation of the bowel lining.

Why is the test requested?

The test may be used particularly in people with:

  • Long-lasting or recurring diarrhoea
  • Abdominal pain
  • Blood or mucus in the stool
  • Diarrhoea at night
  • Unexplained weight loss
  • Suspected inflammatory bowel disease

It can also be useful in assessing and following disease activity in people already diagnosed with Crohn’s disease or ulcerative colitis.

Why does calprotectin rise?

Among the most important causes of a raised calprotectin are conditions that cause inflammation in the bowel.

Inflammatory bowel disease

  • Crohn’s disease
  • Ulcerative colitis

can raise calprotectin markedly. But these are not the only causes.

Bowel infections

Calprotectin can rise temporarily in bacterial and some other bowel infections.

Some medicines

NSAID painkillers in particular can affect the bowel lining and lead to a rise in calprotectin. Some other medicines and clinical situations also have to be taken into account when the result is being interpreted.

Other bowel conditions

Calprotectin can also be found raised in diverticulitis, in some colorectal conditions and in other situations that cause inflammation in the bowel.

Does a raised calprotectin mean cancer?

No.

Calprotectin is not a cancer test. It is not used for bowel cancer screening, and a high calprotectin result does not on its own mean cancer.

But because calprotectin can be raised in some colorectal conditions, the result has to be weighed together with your age, your symptoms and your other findings.

What should calprotectin be?

Giving a single number here is not always right.

Reference values can vary with the laboratory and the method used.

In many laboratories values below roughly 50 µg/g are taken as normal for adults. Values above that may be classified, depending on the laboratory’s method, as borderline, mildly raised or raised.

In some laboratory and clinical approaches, values around 50–120/150 µg/g are taken as borderline or mildly raised, and repeating the test may be considered depending on the clinical picture. More marked rises increase the likelihood of bowel inflammation.

But the number on its own does not make a diagnosis.

What does it mean if calprotectin is very high?

In general, the higher the calprotectin level, the greater the likelihood of active inflammation in the bowel.

Values of several hundred µg/g and above matter more for organic and inflammatory bowel disease, particularly where the patient’s symptoms fit as well. However:

“Calprotectin came back 500 = Crohn’s disease” is not an equation that can be made.

Other causes, such as a bowel infection, can also produce quite high values.

What is done if calprotectin is mildly raised?

For mildly or borderline raised results your doctor will weigh:

  • Your symptoms
  • Your age
  • Alarm features
  • The medicines you take
  • Any recent bowel infection
  • Your blood tests
  • Your previous calprotectin results

If needed, the calprotectin test may be repeated after a certain interval. A single mildly raised result should not lead straight to a diagnosis of Crohn’s disease.

Does a raised calprotectin mean a colonoscopy is needed?

Not every raised calprotectin leads automatically to a colonoscopy.

Whether a colonoscopy is needed is decided by weighing the calprotectin level, your age, your symptoms, alarm features, your blood tests and your family history together.

If calprotectin is markedly and persistently raised, or if there are symptoms suggesting inflammatory bowel disease, colonoscopy and — where needed — biopsies may come into consideration.

Does calprotectin rise in IBS?

Irritable bowel syndrome (IBS) is a functional bowel condition, and marked bowel inflammation is not a typical feature of IBS.

For this reason faecal calprotectin can be used in suitable patients to help distinguish IBS from inflammatory bowel disease. A normal or low calprotectin value helps reduce the likelihood of active inflammatory bowel disease in the right clinical setting.

But a calprotectin result does not on its own make a diagnosis of IBS either.

Does the test need repeating?

Sometimes it does. Your doctor may want to repeat the test particularly if:

  • The result is borderline or mildly raised
  • There has been a recent bowel infection
  • You are taking a medicine that could affect the result
  • The result does not fit with previous ones

In patients with a diagnosis of Crohn’s disease or ulcerative colitis, serial measurements can be used to follow disease activity.

Should I stop my medicines before the test?

Do not stop medicines on your own

Some medicines, particularly NSAID painkillers, can affect the calprotectin result. Tell your doctor about all the medicines you take. Whether a medicine is stopped is a decision for your doctor.

Which symptoms matter particularly?

Assessment should not be delayed if a raised calprotectin is accompanied by any of the following:

  • Obvious blood in the stool
  • Unexplained weight loss
  • Diarrhoea that wakes you from sleep
  • Fever
  • Iron deficiency or anaemia
  • Long-lasting or worsening diarrhoea
  • Severe or worsening abdominal pain
  • A family history of inflammatory bowel disease or colorectal cancer

Where these are present, the patient needs assessing as a whole rather than by the calprotectin result alone.

How is the cause of a raised calprotectin looked into?

Your doctor will first assess your symptoms and your medical history. Where needed, the following may be used:

  • Full blood count
  • CRP and other inflammatory markers
  • Iron and ferritin
  • Stool tests
  • Tests for infection
  • Colonoscopy and biopsy
  • Imaging

Which investigation is needed differs from person to person.

Remember

  • A normal calprotectin Helps reduce the likelihood of marked active inflammation in the bowel.
  • A mild or borderline rise Can be caused by infection, medicines or other reasons; reassessment may be needed depending on the clinical picture.
  • A marked and persistent rise Should be investigated for bowel inflammation.
  • A high calprotectin Is not on its own a diagnosis of Crohn’s disease, ulcerative colitis or cancer.

This is not enough to make a diagnosis

A faecal calprotectin result should not be judged on its own.

What it means has to be weighed together with the calprotectin level, the laboratory’s reference range, your age, your symptoms, the medicines you take, your other laboratory results and, where needed, endoscopic examination.

Sources

  1. Prof. Ali Tüzün İnce, MD

Prof. Ali Tüzün İnce, MD — https://www.alituzunince.com/en/test-results/faecal-calprotectin/