Calprotectin (Fecal) levels, explained
Fecal calprotectin is a protein released by white blood cells in the gut lining — a stool test that shows whether bowel symptoms come from true inflammation or not.
What’s a normal Calprotectin level?
Typical adult reference range, shown for orientation. Your report’s range may differ by lab, age, and sex — the analyzer uses your report’s own ranges when available.
What high and low Calprotectin mean
A value outside the reference range is a flag, not a diagnosis. Here’s what each direction usually points to — and the most common causes.
High calprotectin means there is active inflammation in the bowel wall — most often inflammatory bowel disease, but also infection, NSAID use, and occasionally polyps or cancer.
- Crohn’s disease or ulcerative colitis (active or flaring)
- Gut infection (bacterial gastroenteritis, C. difficile)
- Regular NSAID or aspirin use
- Colorectal polyps or cancer, diverticulitis, or microscopic colitis
A low calprotectin is the reassuring result — bowel symptoms are very unlikely to be caused by inflammation, pointing towards irritable bowel syndrome or a non-inflammatory cause.
- No significant gut inflammation (the normal state, including IBS)
- IBD in remission
When a Calprotectin result needs attention
Values over 150–200 µg/g usually indicate active inflammation and warrant gastroenterology assessment; 50–150 µg/g is borderline and is typically repeated in a few weeks. Any raised value with rectal bleeding, weight loss, night-time symptoms, or anemia should be reviewed promptly regardless of the number.
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Calprotectin (Fecal) — frequently asked questions
- What does a high calprotectin mean?
- That white blood cells are passing into the bowel wall, which happens with inflammation. The usual causes are Crohn’s disease, ulcerative colitis, gut infections and regular NSAID use. The higher the value, the more likely significant inflammation is; levels in the hundreds typically lead to a colonoscopy to find the cause.
- Calprotectin vs IBS — can it tell them apart?
- That is its main job. IBS does not inflame the bowel, so calprotectin stays normal; inflammatory bowel disease raises it. A normal result in someone with typical IBS symptoms and no red flags makes IBD very unlikely and often avoids an invasive investigation.
- What is a normal calprotectin level?
- Under 50 µg/g is normal in adults. 50–150 µg/g is a grey zone, often repeated after stopping NSAIDs and any infection has cleared. Over 150–200 µg/g suggests active inflammation. Children under four normally run higher, and ranges vary slightly between laboratories.
Related lab markers
- CRP (C-Reactive Protein) →CRP is a protein made by the liver that rises with inflammation anywhere in the body — a general marker of inflammatory activity.
- Hemoglobin →Hemoglobin is the protein in red blood cells that carries oxygen — low hemoglobin defines anemia.
- Ferritin →Ferritin is the protein that stores iron in your body — it is the single best blood marker of how much iron you have in reserve.
- All lab markers →Browse every biomarker guide in one place.
This page provides educational health information and does not replace professional medical advice, diagnosis, or treatment. Interpret any lab value with your clinician, who has your full medical context. For emergencies, contact emergency services.