The best test currently available to assess intestinal inflammation, the type that occurs with Crohn's disease or ulcerative colitis, is an endoscopy. An endoscopy is a flexible tube with a small light and scope or camera at the end. The two most frequently used endoscopies to detect intestinal inflammation are the colonoscopy (which views the entire colon) and the sigmoidoscopy (views only the first third of the colon).
More recently, a new test called fecal calprotectin test has been used to provide an accurate yet less invasive assessment of possible inflammation of the intestine. Calprotectin is a major protein found in inflammatory cells. The test is performed by collecting a stool sample and having it analyzed at a lab. If calprotectin is found in the sample, it is a good indicator of possible inflammation, even before the onset of severe symptoms, and would usually warrant further testing.
Though the fecal calprotectin test is not used to diagnose specific conditions, it may be used as a first step to determine whether an endoscopy is warranted. In certain circumstances the use of the calprotectin test may allow the person to avoid having a colonoscopy Your doctor may also order a fecal calprotectin test to help explore the cause of certain symptoms associated with a flare-up, such as abdominal pain or diarrhea.
Though elevated calprotectin indicates that inflammation is present, the test is not able to pinpoint the exact location of the inflammation or help diagnose the specific condition that is causing it. Generally, higher levels of calprotectin are associated with more severe inflammation. It is not uncommon that those newly diagnosed with Crohn's disease or ulcerative colitis may have high levels of calprotectin.
A high level of calprotectin, even in the absence of symptoms, may mean that a person’s Crohn's or colitis is not adequately controlled. In this scenario a change in medical management maybe warranted to better treat inflammation caused by the diseases to avoid future complications.
A low level of calprotectin typically means that the symptoms are the result of a non-inflammatory bowel disorder, such as irritable bowel syndrome, and therefore a colonoscopy might not be needed.
Studies have shown that the use of screening with fecal calprotectin could reduce the number of adult endoscopies by 67% and 35% in children and teens. The potential downside of screening is that in some cases it might lead to delayed diagnoses and treatment.