Determination of calprotectin

An inflammatory marker for the diagnosis and monitoring of inflammatory bowel disease. Only a small proportion of patients with abdominal pain have organic disease, but the correct diagnosis can rarely be made after clinical examination. The acute phase calprotectin protein allows us to distinguish between organic and functional intestinal diseases.

Fecal calprotectin is a calcium binding protein. It is present in large quantities in neutrophils, as well as in the cytoplasm of monocytes and macrophages. Calprotectin is a product of neutrophilic granulocytes, the detection of which in feces indicates inflammation in the intestinal wall. These proteins include lactoferin, lysozyme, elastase, myeloperoxidase and calprotectin. Among them, lactoferrin and calprotectin are the most stable and are slowly decomposed by microbial proteases, which makes it possible to study their concentrations. Due to this, they are classified as biomarkers of "fecal inflammation".

Calprotectin is stable in feces for over 7 days at room temperature and is evenly distributed in it. With active inflammatory bowel disease, there is an increased migration of white blood cells from blood vessels to the inflamed intestinal mucosa. Due to the release of white blood cells also into the intestinal lumen, pro-inflammatory proteins such as calprotectin can be measured in feces. The concentration of calprotectin in feces is directly proportional to the intensity of neutrophil infiltration in the intestinal mucosa. It was found that the concentration of calprotectin correlates with signs of activity in both ulcerative colitis (hereinafter referred to as UC) and Crohn's disease (hereinafter referred to as CD). Bleeding from the intestinal wall has a slight effect on the concentration of calprotectin in the stool, and increases its concentration by no more than 10 mcg /g. An increase in the concentration of fecal calprotectin of more than 120 mcg/g is detected in more than 90% of patients with inflammatory bowel diseases at the stage of primary diagnosis.

The detection of fecal calprotectin makes it possible to differentiate patients with irritable bowel syndrome from the organic causes of damage to the gastrointestinal tract (hereinafter referred to as the gastrointestinal tract). Moderately elevated values of calprotectin are noted in mucosal lesions (celiac disease, lactose deficiency, autoimmune gastritis), significantly increased concentrations are noted in inflammatory bowel diseases, bacterial infections of the gastrointestinal tract, diverticula and oncological diseases, constant intake of nonsteroidal anti-inflammatory drugs (NSAID). The concentration of fecal calprotectin is higher in newborns and children under 1 year of age exceeds 500 mcg/g, therefore, the determination of calprotectin should be used with caution in children under 4 years of age.

Fecal calprotectin is a simple, non-invasive and sensitive test to assess disease activity and response to therapy in those patients who have a confirmed diagnosis of inflammatory bowel diseases. The advantage of studying fecal calprotectin in CD is that elevated concentrations may reflect segmental lesions of the small intestine, which is inaccessible for endoscopic and histological analysis. Persistent elevated levels of fecal calprotectin may indicate the ineffectiveness of therapy, in addition, an increase in calprotectin content is noted with an approaching exacerbation of the disease. Due to its low specificity, fecal calprotectin cannot replace instrumental methods for the diagnosis of Crohn's disease. Histological analysis is the "gold standard" of diagnosis and the combination of endoscopic and imaging methods makes it possible to clarify the volume and distribution of intestinal lesions. To a certain extent, the analysis of fecal calprotectin in combination with stool reaction to latent blood and specific complaints makes it possible to select patients for colonoscopy. Since the concentration of fecal calprotectin in the stool directly correlates with the histological and endoscopic activity of the disease, persistently elevated levels of fecal calprotectin may indicate the ineffectiveness of therapy, in addition, an increase in the calprotectin content in dynamics is noted with an approaching exacerbation of the disease.

What can affect calprotectin levels?

In children under 1 year of age, calprotectin concentrations >500 mcg/g, up to 4 years of age the normal concentration of FKP is <100 mcg/g (Canani et al, 2004);
Calcium, magnesium and zinc rich drugs/ supplements and laxatives may affect the results of the test;
Calprotectin is elevated in food allergies such as cow's milk (Carroccio et al. 2011), cystic fibrosis (Lee JM, et al. 2012), diverticulitis (Tursi A. et al, 2012), 20% of obese patients;
Calprotectin is elevated in adenovirus, rotavirus, norovirus diarrhea, as well as salmonellosis and campylobacter infection (Chen CC 2012);
Calprotectin is elevated 117(2-306) mcg/g in celiac disease (Balamtek?n et al. 2012), gluten-free diet leads to normalization of concentrations;
Analysis preparation leaflet here.