Fecal Calprotectin: Normal Range + What High Levels Can Mean for Crohn’s
Last Updated Jan 15, 2026
Fecal calprotectin is a stool inflammation test that estimates how much inflammation is happening in the intestines. For many people living with Crohn’s disease, it becomes a familiar number on lab reports, used alongside symptoms, bloodwork, and sometimes imaging or endoscopy. The tricky part is that “normal” and “high” are not always the same across every lab, and a “borderline” calprotectin result can feel confusing. This guide explains common fecal calprotectin ranges, what high levels can mean for Crohn’s, and why repeat testing is sometimes part of the plan.
What fecal calprotectin measures (and why it shows up in Crohn’s care)
Calprotectin is a protein released by certain white blood cells during inflammation. When the intestinal lining is irritated or inflamed, more calprotectin can end up in stool. Because of that, fecal calprotectin is often used as a noninvasive way to check for intestinal inflammation and to help predict active disease. [1]
A key point is that fecal calprotectin reflects inflammation, but it does not name the cause. High values can happen for reasons other than Crohn’s, including some infections and celiac disease, and even certain medicines like nonsteroidal anti-inflammatory drugs (NSAIDs) can raise results. For this reason, a high number often leads to more context questions and sometimes additional testing, rather than an automatic conclusion. MedlinePlus also notes that providers may repeat the test in a few weeks to see whether levels change, and that calprotectin testing can sometimes help avoid unnecessary colonoscopy when inflammation is unlikely. [2]
Another important detail is that calprotectin is usually most helpful when compared over time. A single result matters, but trends (rising, falling, or stable) often fit better into Crohn’s monitoring conversations than one isolated number.
Calprotectin levels chart: normal, borderline, high (and how results fit into flare decisions)
Reference ranges vary by lab and clinic, so the lab’s own “flag” (normal vs abnormal) should be read first. One commonly used set of ranges is: [3]
Fecal calprotectin (mcg/g or µg/g) | How labs may label it | What it can suggest |
|---|---|---|
< 50 | Normal | Inflammation is less likely |
50 to 120 | Borderline | Mild inflammation is possible, sometimes seen with treated inflammatory bowel disease or NSAID/aspirin use |
> 120 | Abnormal | Active intestinal inflammation is more likely |
Some health systems use different cutoffs to guide next steps. For example, National Health Service (NHS) pathways described by the National Institute for Health and Care Excellence (NICE) have used <100 as a “normal” threshold and recommend a repeat test when results fall into an intermediate range (such as 100 to 250), partly because false positives can occur. [4]
When calprotectin is clearly elevated, Crohn’s teams often interpret it as “inflammation is more likely,” then combine that with symptoms and other markers to decide what to do next. In research focused on Crohn’s disease, higher fecal calprotectin has been associated with a greater chance of disease activity or relapse, with some studies using cutoffs such as >150 µg/g when evaluating relapse risk. [5]
When symptoms feel like a flare but calprotectin is normal or borderline, clinicians may consider other explanations (like irritable bowel syndrome, infection, or medication effects) and may use repeat testing to clarify the picture. The goal is usually not to chase a single “perfect” number, but to use calprotectin as one practical data point in a larger Crohn’s monitoring plan.