Can calprotectin distinguish Crohn disease from ulcerative colitis?

No. Calprotectin detects intestinal neutrophilic inflammation but does not distinguish between types of IBD, infections, or other causes of mucosal injury. The diagnosis is made through endoscopy, histology, and clinical features.

Why might calprotectin be elevated in someone without IBD?

Calprotectin rises with any cause of intestinal neutrophil infiltration, including infections, NSAID enteropathy, colorectal neoplasia, microscopic colitis, and diverticulitis. Clinical correlation and, when appropriate, stool culture or colonoscopy are needed to determine the cause.

How is the stool sample collected?

The patient collects a small sample (approximately 5 g) at home using a collection device provided in the kit and ships it to the laboratory according to the instructions. Calprotectin is stable at room temperature for several days.

Can NSAIDs affect the calprotectin result?

Yes. Non-steroidal anti-inflammatory drugs cause mucosal injury and neutrophil infiltration, which can significantly elevate calprotectin. A medication history is essential before interpreting an elevated result.

How often should calprotectin be monitored in patients with IBD?

Frequency depends on disease activity and treatment goals. Monitoring every 2–3 months during dose adjustments or induction therapy, then every 6–12 months during stable remission, is common. Rising levels may signal relapse before symptoms appear.

Does an intermediate calprotectin result (50–250 µg/g) require further action?

Intermediate results are often repeated after a few weeks or correlated with clinical symptoms and other investigations. They may reflect mild inflammation, recent infection, assay variability, or NSAID use, and do not always mandate immediate endoscopy.

How long does it take to receive calprotectin results?

Results are typically available within 5–7 business days from specimen receipt at Diagnostic Solutions, though turnaround may be longer if additional stool analyses are ordered concurrently.

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Calprotectin

Q: What is the difference between faecal calprotectin and serum inflammatory markers?

Faecal calprotectin reflects neutrophilic inflammation within the gut mucosa and is released directly into the bowel lumen, making it specific to intestinal disease. Serum markers such as CRP measure systemic inflammation and are less sensitive for detecting or monitoring mucosal activity in IBD.

Q: What does a normal calprotectin result mean?

A normal result (typically <50 µg/g) has high negative predictive value for active inflammatory bowel disease and suggests that gastrointestinal symptoms are likely functional. It does not exclude quiescent IBD, small-bowel Crohn disease, or non-inflammatory conditions such as coeliac disease.

The calprotectin test quantifies a neutrophil-derived calcium-binding protein in stool to detect and monitor intestinal inflammation. Elevated faecal calprotectin distinguishes inflammatory bowel disease from functional gastrointestinal disorders, correlates with endoscopic activity, predicts relapse, and guides decisions about endoscopy and treatment escalation in IBD.

Biomarkers

Stool

Sample

5–7 business days

Turnaround

Fasting

What is the Calprotectin test?

The Calprotectin test quantifies a neutrophil-derived protein in stool to detect and monitor intestinal inflammation. Practitioners order it as a non-invasive triage tool to identify which patients with chronic diarrhoea, abdominal pain, or other gastrointestinal symptoms require endoscopy, and to distinguish inflammatory bowel disease from functional disorders such as irritable bowel syndrome, which do not elevate calprotectin. In patients with known IBD, serial calprotectin measurements track mucosal inflammation more closely than symptoms or serum markers alone, guide decisions about escalating or de-escalating therapy, and predict clinical relapse before overt symptoms return. Because the result reflects neutrophilic activity within the gut lumen rather than systemic inflammation, it offers direct insight into mucosal health and complements but does not replace endoscopic and histological assessment.

What does the Calprotectin test measure?

FC(Faecal Calprotectin)

Range: <50 µg/g is typically considered normal; values vary by assay and laboratory.Optimal: Thresholds differ by clinical question. Many guidelines use <50 µg/g for normal, 50–250 µg/g as intermediate (often repeated or correlated with symptoms), and ≥250 µg/g as significantly elevated, warranting further investigation or endoscopy.µg/g / mg/kg

Calprotectin is a calcium- and zinc-binding heterodimer (S100A8/A9) that accounts for roughly 60 per cent of the cytosolic protein content of neutrophils. When neutrophils infiltrate the intestinal mucosa in response to inflammation, calprotectin is released into the bowel lumen and remains stable in stool for several days at room temperature, making it a robust non-invasive marker of intestinal neutrophilic inflammation. Unlike inflammatory markers measured in serum, faecal calprotectin directly reflects the inflammatory state of the gut mucosa.

Faecal calprotectin distinguishes organic inflammatory bowel disease from functional gastrointestinal disorders, which typically show normal calprotectin. Elevated concentrations are sensitive for active inflammation in Crohn disease and ulcerative colitis, correlate with endoscopic and histological activity, and are used to monitor disease, predict relapse, and assess mucosal healing after treatment. It is also elevated in infectious enterocolitis, colorectal neoplasia, and drug-induced enteropathy, so clinical context and follow-up are essential.

Why is the Calprotectin test ordered?

Triage of patients with chronic diarrhoea, abdominal pain, or rectal bleeding to determine the need for colonoscopy and distinguish IBD from functional disorders
Monitoring disease activity and mucosal healing in patients with established Crohn disease or ulcerative colitis, especially when symptoms are ambiguous or endoscopy is deferred
Assessment of suspected IBD relapse or flare in patients in clinical remission but with emerging symptoms
Evaluation of response to induction or maintenance therapy for IBD, using serial measurements to guide treatment decisions
Investigation of gastrointestinal symptoms in patients on non-steroidal anti-inflammatory drugs, where NSAID enteropathy may raise calprotectin
Follow-up of acute gastroenteritis to confirm resolution of mucosal inflammation, though most practitioners reserve the test for chronic or recurrent presentations
Post-surgical monitoring in IBD patients after resection, where rising calprotectin may signal endoscopic recurrence before symptoms appear
Screening in first-degree relatives of IBD patients with new gastrointestinal symptoms, though this is not routine practice in all settings

Sample collection and turnaround

Sample type

Stool

Fasting required

Collection method

At-home collection kit

Turnaround

5–7 business days

Collection notes

The patient collects a small stool sample at home using the collection device provided by Diagnostic Solutions, following the laboratory's instructions for aliquot size and handling. The specimen is stable at room temperature during shipping. Avoid collecting during menses or from toilet water; a clean collection container or stool-collection paper is recommended.

Specimen requirements

Approximately 5 g of stool (roughly the size of a walnut) transferred into the collection tube. Calprotectin is stable for several days at ambient temperature; ship according to the kit instructions. Multiple aliquots may be provided for concurrent microbiome or other stool analyses if ordered together.

What can affect Calprotectin results?

elevatesNon-steroidal anti-inflammatory drugs (NSAIDs)

NSAIDs cause small-bowel and colonic mucosal injury with neutrophil infiltration, raising calprotectin independent of IBD; a medication history is essential before interpreting an elevated result.

elevatesProton-pump inhibitors (PPIs)

Long-term PPI use has been associated with microscopic colitis and small-bowel bacterial overgrowth, both of which can modestly raise calprotectin in some patients.

elevatesInfectious gastroenteritis

Bacterial, viral, or parasitic enteric infections provoke acute neutrophilic inflammation and transiently very high calprotectin; repeat testing after resolution confirms whether elevation was infectious rather than chronic inflammatory.

elevatesColorectal neoplasia

Colorectal adenomas and carcinomas can elevate calprotectin, so a raised result in the absence of IBD symptoms warrants age-appropriate colorectal cancer screening or colonoscopy.

variableCollection and storage conditions

Calprotectin is stable in stool for several days at room temperature but prolonged delay or inappropriate storage can degrade the sample; follow the laboratory's collection and shipping instructions.

variableDiarrhoea and stool consistency

Watery stool may dilute calprotectin concentration, though most assays normalise to stool weight; very liquid samples can occasionally produce spuriously low or variable results.

What do Calprotectin results mean?

Elevated

Inflammatory bowel disease (Crohn disease, ulcerative colitis), infectious enterocolitis, colorectal neoplasia, NSAID enteropathy, microscopic colitis, and occasionally diverticulitis or ischaemic colitis. Levels ≥250 µg/g are strongly suggestive of active mucosal inflammation warranting endoscopy; intermediate elevations (50–250 µg/g) are repeated or correlated with clinical context, as they may reflect mild inflammation, recent infection, or assay variability.

Normal

A normal result has high negative predictive value for IBD and suggests that symptoms arise from a functional disorder, though it does not exclude quiescent IBD, small-bowel Crohn disease in some patients, or non-inflammatory pathology such as coeliac disease or bile-acid diarrhoea.

Reduced

Normal or low calprotectin (<50 µg/g) effectively rules out active inflammatory bowel disease and indicates that gastrointestinal symptoms are likely functional. Very low values are not clinically significant.

Note: Calprotectin is a marker of neutrophilic inflammation, not a disease-specific diagnostic test. Elevated values require clinical correlation, stool culture or PCR if infection is suspected, and endoscopy when IBD is likely. Serial results are more informative than a single measurement, and thresholds differ by assay — interpret according to the performing laboratory's reference intervals.

Frequently asked questions

Faecal calprotectin reflects neutrophilic inflammation within the gut mucosa and is released directly into the bowel lumen, making it specific to intestinal disease. Serum markers such as CRP measure systemic inflammation and are less sensitive for detecting or monitoring mucosal activity in IBD.

How to access the Calprotectin test

The Calprotectin reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.

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About this page

Published: October 7, 2026

Last reviewed: October 7, 2026

References:

Torres J, et al. ECCO guidelines on therapeutics in Crohn's disease: medical treatment. J Crohns Colitis. (2020)
Raine T, et al. ECCO guidelines on therapeutics in ulcerative colitis: medical treatment. J Crohns Colitis. (2022)
NICE guideline NG129. Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel. (2013)
D'Haens G, et al. Fecal calprotectin is a surrogate marker for endoscopic lesions in inflammatory bowel disease. Inflamm Bowel Dis. (2012)
van Rheenen PF, et al. Faecal calprotectin for screening of patients with suspected inflammatory bowel disease: diagnostic meta-analysis. BMJ. (2010)

This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.