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Gastrointestinal Health  Marker Guide

Calprotectin


What this marker measures

Calprotectin is a human protein released primarily by neutrophils during intestinal inflammation and measured in the stool. It helps distinguish inflammatory conditions such as inflammatory bowel diseases (IBD) from non-inflammatory conditions such as irritable bowel syndrome (IBS), and to monitor IBD activity and relapse risk1–3. This assay is issued under the European IVDR framework (the assay is classified IVDR Class C) with ARTG listing for use in Australian markets

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Assay indications 
Adapted from the instructions for use  
Faecal calprotectin levels correlate significantly with histologic and endoscopic assessment of disease activity in Crohn’s disease and ulcerative colitis. Elevated levels of calprotectin are a much better predictor of relapse than standard inflammatory markers (CRP, ESR, Hb). 
- Discrimination between patients with inflammatory bowel disease (acute Crohn’s disease and ulcerative colitis) and irritable bowel syndrom
- Marker for acute inflammation 
- Parameter for monitoring Crohn’s disease, ulcerative colitis, or the patient’s status after removal of polyps 
- Estimation of gastrointestinal inflammation degree 

Clinical associations*

Consider this marker when your patient presents with:

Infection
May be elevated in bacterial gastroenteritis and C. difficile infection; interpret alongside stool pathogen testing, symptoms and clinical severity.
Inflammatory bowel conditions
May indicate intestinal inflammation in suspected or diagnosed IBD, including ulcerative colitis and Crohn's disease.
Medication effects
May be elevated in patients using NSAIDs or PPIs and should be considered when interpreting results.

*In addition to the assay’s intended use, all clinical associations have been reviewed by the Microba science team to ensure clinical validity supported by Microba’s cited literature.

Interpreting the result

All results are compared to Microba's healthy cohort to determine whether they fall within or outside the expected range.

IN RANGE
≤ 50ug/g. Within the reference range.
Neutrophil-driven intestinal inflammation is unlikely. In patients with known IBD, an in-range result may support treatment response or remission.
BORDERLINE
50ug/g – 100ug/g.
May indicate low-grade intestinal inflammation, recent infection, medication effects, or biological variation. Consider symptoms, NSAID/PPI use, and other inflammatory markers; repeat testing may be appropriate if clinically indicated.
OUT OF RANGE
> 100 ug/g. Above the reference range.
Indicates increased intestinal inflammation but is not specific to the cause. May be associated with IBD, infectious or microscopic colitis, untreated coeliac disease, diverticulitis, or medication-related enteropathy. Referral is recommended if the cause is unclear, the elevation persists, or red-flag symptoms are present.

Patient management insights

Investigate the underlying cause of elevated calprotectin. Adjunctive dietary or supplement strategies may be considered only once the clinical context is established.

Clinical significance
Out-of-range calprotectin requires referral to a medical practitioner if the cause is unknown, the elevation is persistent or red-flag symptoms are present.
Grade C
Dietary strategies
Inclusion of 3 serves per day of polyphenol-rich foods may reduce faecal calprotectin in elderly nursing home residents7.  GRADE D

Mediterranean diet as an adjunct to standard therapy, may be associated with lower faecal calprotectin in patients with IBD4–6.  GRADE C
Supplementation
Inclusion of 3 serves per day of polyphenol-rich foods may reduce faecal calprotectin in elderly nursing home residents7.  GRADE D

Mediterranean diet as an adjunct to standard therapy, may be associated with lower faecal calprotectin in patients with IBD4–6.  GRADE C

Tips for discussing out-of-range results

Your result shows elevated calprotectin, which may suggest intestinal inflammation. This does not identify the exact cause, so we’ll review your symptoms, medications, and other test results to decide what next steps are needed.

Evidence grading for patient management insights
The letter grades shown next to each patient management insight show the quality of the research behind it. Every insight provided has been through a rigorous review of the scientific literature and graded using the NHMRC Levels of Evidence, so you can see exactly how strong the evidence is before applying it in practice.

Calprotectin — Reference sourcesSource references for all clinical associations, interpretation definitions, and patient management insights on this card.

1. Dajti, E. et al. Systematic review with meta-analysis: Diagnostic performance of faecal calprotectin in distinguishing inflammatory bowel disease from irritable bowel syndrome in adults. Alimentary Pharmacology & Therapeutics 58, 1120–1131 (2023).
2. Rokkas, T., Portincasa, P. & Koutroubakis, I. E. Fecal calprotectin in assessing inflammatory bowel disease endoscopic activity: a diagnostic accuracy meta-analysis. J Gastrointestin Liver Dis 27, 299–306 (2018).
3. Mosli, M. H. et al. C-Reactive Protein, Fecal Calprotectin, and Stool Lactoferrin for Detection of Endoscopic Activity in Symptomatic Inflammatory Bowel Disease Patients: A Systematic Review and Meta-Analysis. Am J Gastroenterol 110, 802–819; quiz 820 (2015).
4. Godny, L. et al. Mechanistic Implications of the Mediterranean Diet in Patients With Newly Diagnosed Crohn’s Disease: Multiomic Results From a Prospective Cohort. Gastroenterology 168, 952-964.e2 (2025).
5. Haskey, N. et al. A Mediterranean Diet Pattern Improves Intestinal Inflammation Concomitant with Reshaping of the Bacteriome in Ulcerative Colitis: A Randomised Controlled Trial. J Crohns Colitis 17, 1569–1578 (2023).
6. Chicco, F. et al. Multidimensional Impact of Mediterranean Diet on IBD Patients. Inflamm Bowel Dis 27, 1–9 (2021).
7. Marino, M. et al. A (poly)phenol-rich diet reduces serum and faecal calprotectin in older adults with increased intestinal permeability: the MaPLE randomised controlled trial. BMC Geriatr 24, 707 (2024).
8. Morshedzadeh, N. et al. Effects of flaxseed and flaxseed oil supplement on serum levels of inflammatory markers, metabolic parameters and severity of disease in patients with ulcerative colitis. Complementary Therapies in Medicine 46, 36–43 (2019).
9. Scaioli, E. et al. Eicosapentaenoic Acid Reduces Fecal Levels of Calprotectin and Prevents Relapse in Patients With Ulcerative Colitis. Clinical Gastroenterology and Hepatology 16, 1268-1275.e2 (2018).
10. Prossomariti, A. et al. Short-term treatment with eicosapentaenoic acid improves inflammation and affects colonic differentiation markers and microbiota in patients with ulcerative colitis. Sci Rep 7, 7458 (2017).
11. Banerjee, R. 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 55, 702–708 (2021).
12. Lang, A. et al. Curcumin in Combination With Mesalamine Induces Remission in Patients With Mild-to-Moderate Ulcerative Colitis in a Randomized Controlled Trial. Clinical Gastroenterology and Hepatology 13, 1444-1449.e1 (2015).
13. Hanai, H. et al. Curcumin Maintenance Therapy for Ulcerative Colitis: Randomized, Multicenter, Double-Blind, Placebo-Controlled Trial. Clinical Gastroenterology and Hepatology 4, 1502–1506 (2006)
.14. Dryden, G. W., Lam, A., Beatty, K., Qazzaz, H. H. & McClain, C. J. A Pilot Study to Evaluate the Safety and Efficacy of an Oral Dose of (−)-Epigallocatechin-3-Gallate–Rich Polyphenon E in Patients With Mild to Moderate Ulcerative Colitis. Inflammatory Bowel Diseases 19, 1904–1912 (2013).
15. Biedermann, L. et al. Bilberry ingestion improves disease activity in mild to moderate ulcerative colitis — An open pilot study. Journal of Crohn’s and Colitis 7, 271–279 (2013).
16. Zhou, W. Saccharomyces boulardii powder combined with mesalazine for treatment of active ulcerative colitis: Curative effect and impact on fecal calprotectin and serum inflammatory factors. World Chinese Journal of Digestology 25, 2065 (2017).
17. Neyrinck, A. M. et al. Prebiotic dietary fibre intervention improves fecal markers related to inflammation in obese patients: results from the Food4Gut randomized placebo-controlled trial. Eur J Nutr 60, 3159–3170 (2021)
.18. Valcheva, R. et al. Inulin-type fructans improve active ulcerative colitis associated with microbiota changes and increased short-chain fatty acids levels. Gut Microbes 10, 334–357 (2019).
19. Casellas, F. et al. Oral oligofructose-enriched inulin supplementation in acute ulcerative colitis is well tolerated and associated with lowered faecal calprotectin. Alimentary Pharmacology & Therapeutics 25, 1061–1067 (2007).
20. Langmead, L. et al. Randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis. Alimentary Pharmacology & Therapeutics 19, 739–747 (2004).

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THESE PRODUCTS ARE ONLY AVAILABLE FOR PURCHASE THROUGH A HEALTHCARE PROFESSIONAL.
1.The quantitative faecal occult blood, polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assays (ELISA) used in the Microbiome Explorer range are diagnostic and are approved for clinical use.
2.The faeces pH assay used in the Microbiome Explorer range is for research use only and not to be used as a basis for diagnosis. The metagenomic assays used in the Microbiome Explorer range are to determine the microbiome populations and associated functional pathways in a faecal sample. The application is for research use only and not to be used as a basis for diagnosis. Learn more about the journey we are on to validate this gold-standard technology for clinical diagnosis and application.
3. The Microbiome Explorer range is intended for adults 18 years or older only.

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