Short answer
Fecal calprotectin is a stool test that can help detect inflammation in the intestines. It is often used when the question is IBD vs IBS, or when a clinician wants to know whether diarrhea or pain looks inflammatory enough to justify more workup. It does not diagnose Crohn's disease or ulcerative colitis by itself.
How to interpret the result
| Result context | What it can suggest | Why it matters |
|---|---|---|
| Low or normal | Active intestinal inflammation is less likely. | IBS and some other non-inflammatory causes become more likely, but symptoms still matter. |
| Borderline | Could be early disease, infection, medication effect, or sampling variability. | Repeat testing or GI follow-up is often more useful than reacting to one number. |
| Clearly elevated | Inflammation is more likely. | Further evaluation may include stool pathogen testing, blood tests, medication review, or colonoscopy. |
What can raise calprotectin
| Factor | Why it matters | Follow-up question |
|---|---|---|
| IBD flare | Calprotectin may rise with intestinal inflammation. | Do symptoms and trends match known disease? |
| Infection | Some infections can raise stool inflammation markers. | Are stool pathogen tests needed? |
| NSAID use | Some medicines can irritate the gut and affect results. | Should medication use be reviewed before repeating the test? |
| Other inflammatory disease | Microscopic colitis, celiac disease, diverticulitis, and some cancers can also elevate it. | Does the result fit the rest of the clinical picture? |
When follow-up matters more
Follow-up matters more when the result is clearly high, the symptoms are worsening, or there are alarm features such as blood in stool, fever, dehydration, weight loss, anemia, or persistent night symptoms. In those settings, stool pathogen testing, medication review, GI referral, or colonoscopy may be more useful than treating the number as a stand-alone score. Immunocompromise or a known IBD diagnosis also lowers the threshold for clinician review.
Questions to ask
- Was the sample collected and stored according to instructions?
- Is the result mildly elevated or strongly elevated?
- Could infection, NSAIDs, recent illness, or known IBD explain it?
- Would repeat testing, blood tests, stool pathogen testing, colonoscopy, or GI referral be appropriate?
Related guides: fecal calprotectin vs lactoferrin, stool WBC test and inflammatory diarrhea, post-infectious IBS testing questions, and stool test vs microbiome test.
When a broader workup matters more
Fecal calprotectin can help distinguish inflammation from a functional symptom pattern, but it does not prove the cause. If symptoms persist or red flags are present, infection testing, celiac workup, imaging, or endoscopy may still be needed.
FAQ
What does a high fecal calprotectin mean?
A higher result suggests intestinal inflammation, but it does not say exactly why the inflammation is there.
Can fecal calprotectin distinguish IBD from IBS?
It helps separate inflammatory from non-inflammatory patterns, but it does not diagnose Crohn's disease or ulcerative colitis by itself.
What can raise calprotectin besides IBD?
Infection, NSAID use, other inflammatory gut conditions, and some cancers can raise stool calprotectin.
Why do doctors care about the number?
The degree of elevation helps decide whether more testing, repeat testing, medication review, or endoscopy is more appropriate.
When is repeat testing useful?
Repeat testing can help when the result is borderline, when medications or infection may have distorted the first sample, or when symptoms change.
Does a normal result rule out every gut problem?
No. It lowers the chance of active intestinal inflammation, but symptoms can still come from IBS, reflux, food intolerance, infection, or another cause.