Calprotectin Crohn's disease

Calprotectin in stool (feces) examination: alternative to internal bowel examination to rule out Crohn's disease.

When Crohn's disease or other chronic intestinal inflammation is suspected, stool tests can be used to diagnose Crohn's disease. Previously, this required an extensive bowel examination. Coloscopy (examination using a viewing instrument) is now only necessary when there is a strong suspicion.

The result is good if it is below 50 μg/g.

The result of calprotectin may be incorrectly lowered in watery stools (dilution defect). The higher the inflammation the higher the result, because calprotectin is a reliable marker of inflammation. The result may be slightly lower in dilute stools, but is still significant.

Calprotectin results can be false positive due to intake of certain medications: some medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), can increase levels of calprotectin in the stool.

Calprotectin in stool results from a calcium-binding protein complex of neutrophils and monocytes. It is a sensitive marker of inflammation as well as malignant intestinal diseases. This is particularly true in non-bleeding polyps in colon cancer.

In a large study (Langhorst J., et al, Am J Gastroenterol 2008 103 :. 162-169), Calprotectin was shown to have a sensitivity of 82% and specificity of 87% in distinguishing irritable bowel syndrome (PDS) from inflammatory bowel disease such as Crohn's disease.

This test is meant for diagnosis, not for monitoring. A result above 50 μg/g indicates inflammation. The test measures up to 1600.