Written by the Nuvirox Research Team
Key points
- Fecal calprotectin is a protein released by white blood cells in the gut wall. A stool test measures it as a marker of intestinal inflammation.
- Its biggest strength is ruling things out: a low result makes inflammatory bowel disease very unlikely in adults with IBS-type symptoms.
- Its weakness is false positives. Common medications such as PPIs and NSAIDs, plus older age, can push results above the cutoff without any bowel disease.
Short answer: fecal calprotectin is a stool test that measures a protein shed by inflammatory white blood cells in the intestine, and its main job is to separate gut inflammation (such as inflammatory bowel disease) from non-inflammatory problems like irritable bowel syndrome. A low result is strongly reassuring — in adults with IBS-like symptoms, a value at or below about 40–50 µg/g puts the chance of IBD at around 1% or less. A high result is a prompt for follow-up, not a diagnosis: medications like proton pump inhibitors and anti-inflammatory painkillers, infections, and older age can all raise it.
What is calprotectin, and why is it in stool?
Calprotectin is a protein found mainly inside neutrophils, the white blood cells that rush to sites of inflammation. When the intestinal lining is inflamed, neutrophils migrate into the gut wall and lumen, and calprotectin ends up in the stool in proportion to that activity. It's remarkably stable at room temperature, which is why it works well as a mail-in or clinic stool test.
It's a different kind of measure from blood markers like CRP. Blood tests reflect inflammation anywhere in the body; calprotectin is specific to the bowel. If you've had blood work flagged for inflammation, our explainers on what a high CRP means and what a high white blood cell count means cover the whole-body side.
What is a normal fecal calprotectin level?
Many labs use 50 µg/g as the upper limit of normal, but the right cutoff shifts with age. A study of 132 healthy volunteers proposed upper reference limits of under 166 µg/g for children aged 2–9, under 51 µg/g for ages 10–59, and under 112 µg/g for people 60 and older [6]. In other words, a result of 90 µg/g means something different for a 30-year-old than for a 70-year-old.
| Age group | Proposed upper reference limit | What it means |
|---|---|---|
| 2–9 years | <166 µg/g | Young children naturally run higher |
| 10–59 years | <51 µg/g | Close to the common 50 µg/g lab cutoff |
| 60+ years | <112 µg/g | Mild elevations are more common with age |
Reference limits from Joshi et al. 2010 [6]. Your lab's own range takes priority.
What human studies actually show
van Rheenen 2010 (BMJ meta-analysis). Pooling 13 studies, calprotectin screening in adults had a sensitivity of 0.93 and specificity of 0.96 for IBD. Using it to decide who needs endoscopy would cut adult scopes by about two-thirds, at the cost of delayed diagnosis in roughly 6% of adults with IBD who'd test negative [1].
Menees 2015 (ruling out IBD in IBS). Across eight calprotectin studies, a value of 40 µg/g or lower (or a CRP of 0.5 mg/dL or lower) meant a 1% or lower probability of IBD in adults with IBS symptoms. Importantly, none of the biomarkers could distinguish IBS from healthy people — calprotectin rules out inflammation; it doesn't diagnose IBS [2].
Dajti 2023 (the positive-predictive-value problem). In 17 studies with nearly 2,000 adults, calprotectin had 85.8% sensitivity and 91.7% specificity for separating IBD from IBS. But when IBD prevalence is low — about 1%, as in many primary-care settings — a negative result is right 99.8% of the time while a positive result is right only about 9% of the time. All included studies were at high or unclear risk of bias [3].
Rendek 2023 (medication false positives). In a randomized trial of 32 healthy volunteers, two weeks of omeprazole pushed 53% above the normal limit, diclofenac 39% (with one value as high as 1,080 µg/g), and the combination 69%. Levels returned to normal two to three weeks after stopping, leading the authors to recommend retesting at least three weeks after these drugs are discontinued [4].
Lundgren 2019 (real-world confirmation). Among 590 people with a normal colonoscopy, 36% still had calprotectin above 50 µg/g. PPI use roughly quadrupled the odds of an elevated result, and NSAIDs, aspirin, and age each raised them too [5].
Can calprotectin be high without IBD?
Yes, frequently. Beyond PPIs and NSAIDs, infections (bacterial gastroenteritis), diverticular inflammation, polyps, colorectal cancer, and other bowel conditions can raise it. That's why a single mildly elevated value usually leads to a repeat test — ideally off interfering medications if your clinician agrees — before anyone reaches for a colonoscopy. Very high values, or high values with red-flag symptoms, are another matter and are typically investigated promptly.
Diet is a common question here. Food additives such as emulsifiers have been studied for effects on gut inflammation; in a 2026 randomized trial, five common emulsifiers did not change fecal calprotectin in healthy adults (see our analysis of whether emulsifiers cause inflammation).
What about turmeric and calprotectin?
The honest answer is that curcumin hasn't been shown to lower calprotectin in people. Several trials have tested curcumin as an add-on to standard medication in ulcerative colitis, and these are disease-treatment studies we discuss only as research, not as a reason to self-treat. Two trials reported higher remission rates when curcumin was added to mesalamine [7, 8], but neither abstract reported calprotectin results. A low-dose trial (450 mg/day for eight weeks) found no benefit at all [9]. And a 2024 randomized trial of curcumin, with or without piperine, in people with IBD found no change in fecal calprotectin or inflammatory cytokines over 12 weeks [10].
If you have IBD or a high calprotectin result, any supplement decision belongs in a conversation with your gastroenterologist.
What a calprotectin test won't tell you
It won't tell you which condition you have, where in the gut the inflammation is, or whether your symptoms are IBS. A normal result doesn't exclude every serious problem either — the van Rheenen analysis estimated a small proportion of adults with IBD test negative [1] — so persistent symptoms still deserve follow-up.
Frequently asked questions
What level of calprotectin is concerning?
Many labs flag anything above 50 µg/g, and values in the low hundreds often prompt a repeat test. Much higher values, especially with symptoms, usually lead to referral for further investigation. Interpretation depends on your age, medications, and symptoms, so your clinician's read matters.
Can omeprazole cause a high calprotectin?
Yes. In a randomized trial, two weeks of omeprazole raised calprotectin above normal in about half of healthy volunteers, and levels took up to three weeks to normalize after stopping.
My calprotectin was high but my colonoscopy was normal. Why?
This is common. In one study, over a third of people with a normal colonoscopy had calprotectin above 50 µg/g, with PPIs, NSAIDs, aspirin, and age all contributing.
Does a normal calprotectin mean I have IBS?
Not exactly. It makes inflammatory bowel disease very unlikely, but it can't confirm IBS. IBS is a clinical diagnosis based on symptoms after other causes are reasonably excluded.
Can diet lower calprotectin?
There's little good evidence that specific foods or supplements lower calprotectin in people without IBD. In IBD, treatment of the underlying disease is what brings it down.
Talk to your clinician first
See a clinician promptly for rectal bleeding, black or tarry stools, unintended weight loss, persistent diarrhea (especially waking you at night), anemia, fever, or a family history of IBD or colorectal cancer — whatever your calprotectin result. If you take a PPI, NSAIDs, or aspirin, mention it before testing, and don't stop prescribed medication without advice.
From Nuvirox
Why we formulated Turmeric with BioPerine
We make a turmeric supplement, and we think the most useful thing we can do on a page like this is be clear about what it can't do. The recurring lesson in the turmeric research is that the plant's active compounds are poorly absorbed on their own, so how a formula is put together matters as much as what's on the front of the bottle. We designed ours with absorption in mind, as a simple daily option for people who want to support a healthy inflammatory response* alongside the basics: sleep, movement, and a decent diet.
It comes with a 60-day money-back guarantee — long enough to actually evaluate it the way the research says you should.
Learn more about Turmeric with BioPerine →The bottom line
Fecal calprotectin is a simple stool test that measures inflammatory activity in the gut. Its best use is reassurance: a low result makes IBD very unlikely in adults with IBS-type symptoms. A high result is a reason for follow-up — often a repeat test off PPIs or NSAIDs — rather than a diagnosis, and normal ranges loosen with age. Turmeric hasn't been shown to change calprotectin in human trials, so treat any result as a conversation starter with your clinician. For the bigger picture, see our overview of the gut–inflammation connection.
References
- van Rheenen PF, Van de Vijver E, Fidler V. Faecal calprotectin for screening of patients with suspected inflammatory bowel disease: diagnostic meta-analysis. BMJ. 2010;341:c3369. DOI: 10.1136/bmj.c3369. PMID: 20634346. PMCID: PMC2904879.
- Menees SB, Powell C, Kurlander J, Goel A, Chey WD. A meta-analysis of the utility of C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin, and fecal lactoferrin to exclude inflammatory bowel disease in adults with IBS. Am J Gastroenterol. 2015;110(3):444–454. DOI: 10.1038/ajg.2015.6. PMID: 25732419.
- Dajti E, Frazzoni L, Iascone V, et al. Systematic review with meta-analysis: diagnostic performance of faecal calprotectin in distinguishing inflammatory bowel disease from irritable bowel syndrome in adults. Aliment Pharmacol Ther. 2023;58(11-12):1120–1131. DOI: 10.1111/apt.17754. PMID: 37823411.
- Rendek Z, Falk M, Grodzinsky E, et al. Oral omeprazole and diclofenac intake is associated with increased faecal calprotectin levels: a randomised open-label clinical trial. Eur J Gastroenterol Hepatol. 2023;35(1):52–58. DOI: 10.1097/MEG.0000000000002473. PMID: 36468569.
- Lundgren D, Eklöf V, Palmqvist R, Hultdin J, Karling P. Proton pump inhibitor use is associated with elevated faecal calprotectin levels. A cross-sectional study on subjects referred for colonoscopy. Scand J Gastroenterol. 2019;54(2):152–157. DOI: 10.1080/00365521.2019.1566493. PMID: 30676120.
- Joshi S, Lewis SJ, Creanor S, Ayling RM. Age-related faecal calprotectin, lactoferrin and tumour M2-PK concentrations in healthy volunteers. Ann Clin Biochem. 2010;47(Pt 3):259–263. DOI: 10.1258/acb.2009.009061. PMID: 19740914.
- Lang A, Salomon N, Wu JC, et al. Curcumin in combination with mesalamine induces remission in patients with mild-to-moderate ulcerative colitis in a randomized controlled trial. Clin Gastroenterol Hepatol. 2015;13(8):1444–1449.e1. DOI: 10.1016/j.cgh.2015.02.019. PMID: 25724700.
- Banerjee R, Pal P, Penmetsa A, et al. Novel bioenhanced curcumin with mesalamine for induction of clinical and endoscopic remission in mild-to-moderate ulcerative colitis: a randomized double-blind placebo-controlled pilot study. J Clin Gastroenterol. 2021;55(8):702–708. DOI: 10.1097/MCG.0000000000001416. PMID: 32889959.
- Kedia S, Bhatia V, Thareja S, et al. Low dose oral curcumin is not effective in induction of remission in mild to moderate ulcerative colitis: results from a randomized double blind placebo controlled trial. World J Gastrointest Pharmacol Ther. 2017;8(2):147–154. DOI: 10.4292/wjgpt.v8.i2.147. PMID: 28533925. PMCID: PMC5421114.
- Martins ASDP, Araújo ORP, Gomes ADS, et al. Effect of curcumin plus piperine on redox imbalance, fecal calprotectin and cytokine levels in inflammatory bowel disease patients: a randomized, double-blind, placebo-controlled clinical trial. Pharmaceuticals (Basel). 2024;17(7):849. DOI: 10.3390/ph17070849. PMID: 39065700.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.