Test Catalog

Test ID: CALPR    
Calprotectin, Feces

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients suspected of having a gastrointestinal inflammatory process


Distinguishing inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS), when used in conjunction with other diagnostic modalities, including endoscopy, histology, and imaging

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Calprotectin, formed as a heterodimer of S100A8 and S100A9, is a member of the S100 calcium-binding protein family. It is expressed primarily by granulocytes and, to a lesser degree, by monocytes/macrophages and epithelial cells. In neutrophils, calprotectin comprises almost 60% of the total cytoplasmic protein content. Activation of the intestinal immune system leads to recruitment of cells from the innate immune system, including neutrophils. The neutrophils are then activated, which leads to release of cellular proteins, including calprotectin. Calprotectin is eventually translocated across the epithelial barrier and enters the lumen of the gut. As the inflammatory process progresses, the released calprotectin is absorbed by fecal material before it is excreted from the body. The amount of calprotectin present in the feces is proportional to the number of neutrophils within the gastrointestinal mucosa and can be used as an indirect marker of intestinal inflammation.


Calprotectin is most frequently used as part of the diagnostic evaluation of patients with suspected inflammatory bowel disease (IBD). Patients with IBD may be diagnosed with Crohn disease or ulcerative colitis. Although distinct in their pathology and clinical manifestations, both are associated with significant intestinal inflammation. Elevated concentrations of fecal calprotectin may be useful in distinguishing IBD from functional gastrointestinal disorders, such as irritable bowel syndrome (IBS). When used for this differential diagnosis, fecal calprotectin has sensitivity and specificity both of approximately 85%. However, it must be remembered that increases in fecal calprotectin are not diagnostic for IBD, as other disorders such as celiac disease, colorectal cancer, and gastrointestinal infections, may also be associated with neutrophilic inflammation.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

< or =50.0 mcg/g (Normal)

50.1-120.0 mcg/g (Borderline)

> or =120.1 mcg/g (Abnormal)

Reference values apply to all ages.

Interpretation Provides information to assist in interpretation of the test results

Calprotectin concentrations of 50.0 mcg/g and lower are not suggestive of an active inflammatory process within the gastrointestinal system. For patients experiencing gastrointestinal symptoms, consider further evaluation for functional gastrointestinal disorders.


Calprotectin concentrations between 50.1 and 120.0 mcg/g are borderline and may represent a mild inflammatory process, such as in treated inflammatory bowel disease (IBD) or associated with nonsteroidal anti-inflammatory drug (NSAID) or aspirin usage. For patients with clinical symptoms suggestive of IBD, retesting in 4 to 6 weeks may be indicated.


Calprotectin concentrations of 120.1 mcg/g and higher are suggestive of an active inflammatory process within the gastrointestinal system. Further diagnostic testing to determine the etiology of the inflammation is suggested.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Elevations in fecal calprotectin are not diagnostic for inflammatory bowel disease (IBD), and normal fecal calprotectin concentrations do not exclude the possibility of IBD. Diagnosis of IBD should be based on clinical evaluation, endoscopy, histology, and imaging studies.


Borderline results in fecal calprotectin may be observed in patients taking nonsteroidal anti-inflammatory drugs (NSAID), aspirin, or proton-pump inhibitors.


For borderline results, repeat testing in 4 to 6 weeks is suggested.


Elevations in fecal calprotectin may be observed in other disease states associated with neutrophilic inflammation of the gastrointestinal system, including celiac disease, colorectal cancer, and gastrointestinal infections.


Falsely decreased concentrations of fecal calprotectin may be observed in patients with neutropenia or granulocytopenia.


Due to the lack of homogenous distribution of calprotectin in fecal material, variability in results may be seen when patients are monitored over time, particularly in samples with high calprotectin concentrations.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Gisbert JP, McNicholl AG, Golmollon F: Questions and answers on the role of faecal calprotectin as a biological marker in inflammatory bowel disease. Digest Liver Dis. 2009;41:56-66

2. Campeotto F, Butel MJ, Kalach N, et al: High faecal calprotectin concentrations in newborn infants. Arch Dis Child-Fetal. 2004;89:F353-F355

3. Dabritz J, Musci J, Foell D: Diagnostic utility of faecal biomarkers in patients with irritable bowel syndrome. World J Gastroentero. 2014;20(2):363-375

4. Fagerberg, UL, Loof L, Merzoug RD, et al: Fecal calprotectin levels in healthy children studied with an improved assay. J Pediatr Gastr Nutr. 2003;37:438-472

5. Sherwood RA, Walsham NE, Bjarnason I: Gastric, pancreatic, and intestinal function. In: Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1398-1420