Help in Clinical Diagnosis: The digestive transit and intestinal health: CALPROTECTIN: Diagnostic test for inflammatory bowel diseases

Fecal Calprotectin as an inflammatory bowel marker.

The calprotectin test is requested when there are signs and symptoms suggestive of gastrointestinal inflammation, and the physician is also interested in distinguishing between inflammatory bowel disease (IBD) and noninvasive inflammatory disease.

Laboratory studies make it possible to determine the amount of calprotectin in the blood or in feces.

The level of calprotectin in feces may be high in certain diseases that cause inflammation of the intestine, such as ulcerative colitis and Crohn’s disease. The determination of this substance in feces is used as a parameter to detect the existence of inflammation in the intestine. It has the added advantage that the follow-up of Inflammatory Bowel Disease, once its diagnosis is a fact, it is possible because if a new outbreak of the disease is suspected both to confirm its activity and to assess its severity, in a comfortable way for the patient.

Being a non-invasive test, the doctor may also request it to assess the use of invasive procedures such as sigmoidoscopy and colonoscopy, depending on the type of intestinal disease.

A simple stool sample from the patient helps us in the diagnosis of inflammatory bowel disease.

What is Calprotectin?

Calprotectin is a protein that is inside certain cells of the human body and especially in some types of leukocytes, mainly in neutrophils and monocytes.

The inflammation is an organism response that occurs only in vascularized connective tissues and arises with the defensive purpose of isolating and destroying the harmful agent as well to achieve maximum possible repair of the tissue or organ damage. If there is an aggression to the organism the defensive barriers are put into operation and the leukocytes form part of the second barrier of our nonspecific defense mechanisms.

In the present case, intestinal health, when there is an inflammatory process, a leukocyte migration to the intestinal lumen occurs through the inflamed mucosa, releasing Calprotectin which is a protein that has antimicrobial properties that will increase its concentration in feces (concentration six times greater than in the plasma) in direct proportion to the degree of intestinal inflammation.

In the clinical laboratory, the availability of fecal markers is undoubtedly a diagnostic tool that allows a simple, rapid, non-invasive and reproducible evaluation of intestinal inflammation and with more advantages than the so-called “acute phase reactants” and the determination of antibodies Versus Ulcerative Colitis and Crohn’s disease, because these systemic markers can be influenced by non-intestinal diseases. Although it is not a specific marker its determination has a great clinical utility in the suspicion of:

A/. – Intestinal Inflammatory Disease: Excellent sensitivity and diagnostic specificity. Is proportional to the severity of the lesions and the extent of them.

B/. – Recurrent abdominal pain, chronic nonspecific diarrhea and colic of the infant. It helps in the discrimination between IBD and functional disorders of the gastrointestinal tract, being the most frequent Irritable Bowel Syndrome (IBS).

C/. – Enteropathy Induced by NSAIDs. Abnormal levels of Calprotectin Fecal have been documented in patients with intestinal damage due to NSAIDs. Fecal calprotectin levels correlate with the degree of intestinal damage, they may be elevated when atrophy of the intestinal villi (in a minority of cases) is extensive.

E/. – Monitoring the treatment of Inflammatory Bowel Disease and prediction of relapse. Their levels increase before clinical presentation in the acute outbreak.


Calprotectin determination is used to monitor response to treatment by replacing endoscopy follow-up. It allows to differentiate Inflammatory Bowel Disease in rest of active disease. The healing of the mucosa is associated with sustained remission. The determination of this protein, in the clinical laboratory, adds a number of advantages in the clinical diagnosis of inflammatory bowel disease because:

  1. Calprotectin is resistant to bacterial degradation.
  2. Calprotectin remains stable in feces up to one week at room temperature.
  3. Calprotectin is not affected by medications and is resistant to the proteolytic activity of digestive enzymes.

 Only the consumption of non-steroidal anti-inflammatory drugs, aspirin (acetylsalicylic acid) included may produce false positives as they may cause intestinal inflammation.


  • British National Institute for Heath and Care Excellence (NICE) .October 2013 to issue a new Guideline on the Use of Fecal Calprotectin as a diagnostic test for inflammatory bowel diseases (NICE diagnostics guidance 11, October 2013; Faecal calprotectin diagnostic tests for Inflammatory diseases of the bowel)
  • The Guideline on Clinical Practice (GPC) of the World Organization of Gastroenterology on Inflammatory Bowel Disease.
  • GPC also from the World Organization of Gastroenterology on Irritable Bowel Syndrome,