How the Fecal Calprotectin Test Is Used in IBD

Physicians use a variety of tests to monitor what's happening inside the digestive tract of people with inflammatory bowel disease (IBD). Using an endoscopy test to look inside the small or large intestine is the best way to find out, but scopes can only be done every so often and physicians need information more frequently than that. That's where the fecal calprotectin test can be helpful because, unlike an endoscopy procedure, it is non-invasive but can give some information that might help in making treatment decisions.

Calprotectin is a type of protein that is found mostly in certain types of white blood cells called neutrophil granulocytes and in other types of white blood cells to a lesser degree. The amount of calprotectin in stools can be measured, and it's been found that people with IBD tend to have more calprotectin in their stool (fecal matter) than people who don't have IBD.

Fast Facts

• Calprotectin is a protein normally found in white blood cells that tends to be in higher amounts in people with IBD.
• A fecal calprotectin test is done on a stool sample.
• Most insurance companies will cover a fecal calprotectin test in order to manage IBD.
• There are variations in "normal" fecal calprotectin levels from person to person.
• Fecal calprotectin levels could be high even though there aren't any severe IBD symptoms.

Why Might People With IBD Have More Calprotectin in Their Stool?

Studies have shown that keeping track of the level of fecal calprotectin in stool is useful in the management of IBD. This is a result of Crohn's disease or ulcerative colitis causing inflammation in the digestive tract. When the inflammation happens in the mucosal layer of the intestines, white blood cells increase in number to fight it off. The white blood cells may then degranulate, which means that they release their contents in order to protect the body's cells from inflammation. Inside the white blood cells is calprotectin (as well as many other chemicals) and when there's more calprotectin in the stool, it's a fair bet that there's more inflammation in the intestine.

How Is a Fecal Calprotectin Test Done?

Measuring fecal calprotectin is usually an easy test to do because all it requires is a stool sample, something that is typically easy to come by without much effort. When a patient is asked to give a stool sample, it will mean catching stool in a sterile container and turning it into a lab, either at a hospital, the doctor's office, or an independent facility. A fecal calprotectin level is usually high during a flare-up and lower during remission, but the test is not infallible. There can be variations in calprotectin levels for a particular person and there are, of course, variations from person to person. It is, however, another tool that a gastroenterologist can use to help people with IBD stay ahead of changes in their disease.

Why Is Fecal Calprotectin Useful in IBD?

Calprotectin is useful for a few reasons: The first is that when it is found in the stool, it is stable for a relatively long period of time. For up to as long as 7 days, the level of calprotectin in a stool sample is going to remain the same, making the test that much easier to do. Another benefit to this test is that the fecal calprotectin level can be detected in even a small stool sample.

Several studies have shown that people with IBD have an elevated amount of calprotectin in their stool when compared to people who do not have IBD (healthy people in these studies are called controls). To determine that this test is useful, studies were done that measured fecal calprotectin levels in people with IBD, which were followed up with an endoscopy test to see how the levels matched up to what was going on in the digestive tract. What researchers discovered was that the people with IBD had higher fecal calprotectin levels were also likely to have inflammation or ulcers caused by IBD somewhere in their digestive tract.

The people in the studies didn't always have more severe IBD symptoms, though, even if their fecal calprotectin levels were high. This was particularly true more often in ulcerative colitis than it was in Crohn's disease. This highlights another benefit of the fecal calprotectin level test because it can potentially give an early warning that some inflammation is happening in the digestive tract even before symptoms start cropping up.

By measuring calprotectin in the stool, practitioners may be able to start down the path of diagnosing IBD in a patient or to assess disease activity in a patient already diagnosed with IBD. The idea is that a simple test, which is non-invasive because it is done on stool, can allay the need for an endoscopy (such as sigmoidoscopy or colonoscopy) in some cases and highlight the need for an endoscopy test in others. The fecal calprotectin test will not replace endoscopy but may help physicians as a screening tool, to determine better if and when further follow-up tests are needed.

In children with IBD, a fecal calprotectin may be especially useful. By using this test, there's a potential for a physician to quickly determine if symptoms are potentially coming from IBD or not, without having to do an invasive test like an endoscopy or a test that involves radiology like a CT scan right off the bat.

Fecal calprotectin levels may also be useful for people who are seeking a diagnosis and IBD is in the mix. A fecal calprotectin could be ordered by a primary care physician or an internist and if it turns out to be high, that could prompt a referral to a gastroenterologist for further evaluation.

Drawbacks

One of the drawbacks of testing fecal calprotectin is the false-negative result or the false-positive result, though these outcomes are not common. A patient may actually have IBD or may have inflammation from the IBD, but the fecal calprotectin level may not be very high. That could mean that there actually is inflammation happening in the digestive tract but the test results are coming back with lower calprotectin levels (although this is not typical). The false-negative may be especially problematic in children and teenagers, who make up a significant portion of patients being diagnosed with IBD.

Is the Fecal Calprotectin Test Covered By Insurance?

Some insurances may cover fecal calprotectin testing for Crohn's disease and ulcerative colitis because it has been shown to be cost-effective. The cost of this test is going to be much lower than an endoscopy or a CT scan. There may be insurance companies that don't cover this test yet on a routine basis because it doesn't have the long history of other tests, and insurance companies tend to be slow to adopt changes. However, there is always the appeal process, and the Crohn's and Colitis Foundation even has a document available that a physician can use to request coverage for the test from an insurance provider.

A Word From Verywell

The fecal calprotectin level test gets much less attention in the IBD world than, say, a colonoscopy does. However, it's a helpful test, especially because it doesn't require anything special, like a prep or a day off from work, to get it done. Not every physician may order this test, so it's worth asking if it's appropriate under certain circumstances. Insurance companies will usually cover it, particularly if it's for a patient with IBD (they know it's cheaper than other tests). There are some cases where the fecal calprotectin might not be coming back with the levels expected, but this is not a common occurrence.