A borderline or high faecal calprotectin result suggests possible inflammation in the bowel. It does not, by itself, diagnose Crohn's disease, ulcerative colitis or cancer. The next step depends on the laboratory's reference range, your symptoms, medicines and previous results, not a number copied from someone else's report.
Key points: use the range printed on your report; distinguish calprotectin from a stool blood test; do not stop prescribed medicines yourself; and arrange a clinical plan rather than repeating tests indefinitely. Severe symptoms need urgent care, regardless of the result.
If you have a report and want help understanding the next step, ask The Online GP about a results-review appointment. Send the full report through the team's secure process, not just the highlighted value.
What does faecal calprotectin measure?
Calprotectin measures a protein released by active immune cells and helps assess inflammation in the intestines. It is useful when a clinician is investigating persistent diarrhoea or considering inflammatory bowel disease, often shortened to IBD. It can also help monitor treatment in someone who already has IBD.
This is different from irritable bowel syndrome, or IBS, which does not itself cause intestinal inflammation. The distinction matters because the symptoms can overlap. A clinician may use calprotectin to help decide which investigations are appropriate, but neither a normal nor an abnormal result replaces the rest of the assessment.
It is also a different test from FIT, the faecal immunochemical test, which looks for blood in stool. One cannot be substituted for the other simply because both use a stool sample. Mayo Clinic's patient guidance, updated in August 2026, makes clear that calprotectin alone cannot diagnose IBD, IBS, coeliac disease or colorectal cancer.
What does a borderline result mean?
A borderline result sits in an intermediate band defined by the laboratory and test method. It may reflect mild inflammation, a medicine effect or another factor that needs interpretation. There is no single universal borderline range or automatic repeat interval that applies to every patient.
For example, the University of Iowa laboratory describes 50-120 micrograms per gram as borderline for its assay and says a repeat in four to six weeks may be suggested when appropriate. Those figures explain one laboratory pathway. They are not instructions to apply to a different UK laboratory report or to delay assessment when symptoms are concerning.
Ask your clinician what the laboratory considers borderline, why repeating would help and what should happen if the result remains raised. A useful plan specifies who will review the repeat and what symptoms should bring the review forward. If your symptoms have changed since the sample was taken, say so before simply ordering the same test again.
Does a high result mean inflammatory bowel disease?
A high result raises the possibility of intestinal inflammation but does not identify its cause. IBD is one possibility; bowel infections and other conditions can also raise calprotectin. The size of the result must be read alongside the history, examination and other findings.
Your doctor may ask about the duration of diarrhoea, blood or mucus, night-time symptoms, pain, fever, weight change, travel and recent illness. Previous bowel disease, family history and the timing of medicine changes can alter the next step. Depending on the picture, further stool tests, blood tests or specialist investigation may be more useful than another isolated calprotectin measurement.
A result labelled normal should not be used to explain away persistent bleeding, unexplained weight loss or worsening symptoms. A reassuring marker answers one part of the question, not every possible cause of digestive symptoms.
Can medicines affect calprotectin?
Some medicines can alter the result, including proton pump inhibitors, aspirin and anti-inflammatory painkillers such as ibuprofen and naproxen. Mayo Clinic advises telling the healthcare team about these medicines and continuing prescribed treatment unless the team tells you otherwise.
Bring the names, doses and dates, including over-the-counter products. Do not stop aspirin prescribed for cardiovascular protection or another important medicine to try to produce a lower number. Your clinician can weigh the reason for the prescription against the purpose and timing of the test.
Sample handling also matters. Follow the instructions supplied with your own kit about collection, storage and return. Different kits have different requirements. If a sample was delayed or contaminated, tell the laboratory or clinician rather than assuming the result is unaffected.
When should symptoms take priority over the test?
Severe or rapidly worsening symptoms need urgent assessment rather than a routine online results discussion. Seek emergency help for severe abdominal pain with collapse, major bleeding, vomiting blood or signs of serious illness. In the UK, use 999 for a life-threatening emergency. Persistent rectal bleeding, significant dehydration, fever or unexplained weight loss should prompt timely medical advice.
A private appointment is not a substitute for emergency care. Equally, someone who is otherwise well with a modestly abnormal result may need an organised review rather than panic. The purpose of interpretation is to make that distinction safely.
What should a private results review include?
A useful review should connect the result to a practical decision: whether to observe, repeat, investigate or refer. Prepare the full report with units and reference values, previous results, a short symptom timeline and your medicine list. If the test was ordered elsewhere, include the original reason and any advice already given.
For care in London or an online review, ask which appointment format is suitable, what is included, whether additional tests or referral letters cost extra and who will review the outcome. The value lies in a coherent plan and clear responsibility for follow-up, not simply access to another test.
Request a review and a complete fee before booking. The team can confirm availability and the appropriate route; a stool test result alone does not establish that a remote appointment is sufficient.
Can I just repeat the test privately?
Repeating can be appropriate, but only when it answers a defined clinical question. Repeating without a plan may delay the investigation that is actually needed. Ask what change would alter management and who will act on the result.
Does borderline calprotectin mean cancer?
No. Borderline calprotectin is not a cancer diagnosis or a cancer exclusion test. Symptoms and the broader clinical picture determine whether another pathway, including testing for bowel bleeding or specialist assessment, is needed.
Your next step
Keep the report, do not change prescribed medicines yourself and arrange a review that ends with a named next action. Contact The Online GP to discuss the right appointment, or use the contact page. If symptoms are urgent, seek urgent care instead of waiting for a reply.
Sources and evidence limits
Mayo Clinic: calprotectin faecal test, updated August 2026. Test purpose, limitations, medicines and collection advice.
University of Iowa: calprotectin laboratory handbook. An assay-specific example, not a universal UK threshold.
Prepared 3 November 2026. General patient information, not an individual diagnosis. Laboratory pathways and clinical needs differ.