Calprotectin Stool Test

When intestinal inflammation attracts neutrophils, these immune cells release calprotectin that can be measured in stool. The result is an indirect signal of inflammation. It does not show where the inflammation is or name its cause.^{See reference 1,See reference 2}

IBD, which includes Crohn’s disease and ulcerative colitis, and IBS can produce overlapping bowel symptoms. Calprotectin helps inform the assessment because these conditions have different underlying processes. Symptoms alone or the calprotectin number alone cannot settle the diagnosis.^{See reference 1,See reference 3}

NICE recommends it as one option to support clinicians assessing certain adults with recent lower gastrointestinal symptoms when specialist assessment is being considered and cancer is not suspected. The recommendation depends on quality assurance and locally agreed care pathways.^{See reference 3}

For children with suspected IBD, the NICE recommendation concerns those referred for specialist assessment. These boundaries matter: a screening result should not be used to decide that concerning symptoms need no further evaluation or that a child should follow an adult pathway.^{See reference 3}

Those cutoffs describe the cited Mayo CALPR assay. mcg/g and µg/g both mean micrograms per gram of stool. Your laboratory may use a different method or reporting pathway, so retain its own interval and comments. A borderline label is not a diagnosis.^{See reference 2,See reference 4}

For example, a result of 90 mcg/g falls in that specific assay’s borderline category. It does not establish Crohn’s disease or determine a treatment. The clinician still needs the symptoms, medical history and other relevant findings.^{See reference 2}

A clinician may repeat an uncertain result or compare it with previous measurements. A trend is most useful when the collection, laboratory and clinical situation are recorded. A change in the number needs interpretation; it is not automatically a treatment success or failure.^{See reference 1,See reference 4}

Keep dates, medicine changes and relevant symptoms with the reports. Ask whether repeat testing is appropriate and what question it would answer. Do not stop an anti-inflammatory medicine, aspirin or an acid-suppressing medicine just to lower the test result.^{See reference 2,See reference 4}

A stool sample is usually collected at home into the supplied container. Keep urine and toilet water out of it, and follow the laboratory’s directions for storage and return. A testing service may reject a sample collected or transported incorrectly.^{See reference 1,See reference 2}

The instructions can differ between services and tests. Use the label and leaflet that came with your container, rather than applying another laboratory’s storage times to your sample.^{See reference 2,See reference 4}

NICE’s adult recommendation explicitly excludes situations where cancer is suspected. A low result does not provide permission to dismiss symptoms or replace an appropriate cancer assessment. Equally, an elevated result does not prove cancer: several causes can produce intestinal inflammation.^{See reference 1,See reference 3}

Discuss persistent or worsening bowel symptoms with a health professional and follow any direct instructions from your care team. The aim is to explain the clinical question, not to make a decision from a coloured laboratory flag.^{See reference 1,See reference 4}