Fecal Calprotectin testing can provide an accurate diagnosis in many patients with chronic diarrhea without the need of doing invasive diagnostic procedures. It is a helpful diagnostic tool to monitor individuals with Inflammatory Bowel Disease (IBD) (Crohn’s disease, Ulcerative colitis) and to distinguish from Irritable Bowel Syndrome (IBS).
Calprotectin is a protein can be considered to be neutrophil-specific. Calprotectin accounts for approximately 60% of total soluble proteins in neutrophils. Neutrophils are the common effector cells that define acute inflammation in response to a number of factors. The amount of calprotectin reflects the number of participating neutrophils in inflammation. The amount of calprotectin in feces provides a noninvasive quantitative measure of neutrophil flux to the intestine; however, it is important to keep in mind that fecal calprotectin is inflammation and not disease-specific.
The normal range of fecal calprotectin is 10 to 50 or 60 μg/mg. While values over 50 or 60 ug/mg are abnormal, levels over 200 μg/mg have a higher positive predictive value for inflammation damage, and values of 500 to 600 μg/mg nearly guarantee those findings.
Fecal calprotectin certainly has the potential to serve as a diagnostic screening test. An abnormal test result indicates intestinal inflammation of any cause. There are numerous intestinal diseases and drugs (eg, NSAIDs, alcohol) associated with low-grade intestinal inflammation with average calprotectin levels between 50 and 300 μg/mg. However, only untreated IBD and certain food infections are associated with very high levels.
This differentiation in very high levels in the presence of chronic diarrhea and bowel discomfort, is a reasonable test used to differentiate between IBD vs. IBS being the cause. Because of this, fecal calprotectin testing is often used to monitor individuals with IBD for active disease.
A fecal calprotectin test is performed by providing a stool sample in a clean container provided by the laboratory. This sample should be uncontaminated by urine or water. It can take 1-2 weeks for the test results to be delivered due to the specialized procedure used to calculate the amount of calprotectin in the sample.
LifeLabs: Fecal Calprotectin Testing
Badgut.com: Fecal Calprotectin Test
Gastroenterol Hepatol (N Y). 2017 Jan; 13(1): 53–56.
Last updated on Jan 12, 2021