Predicting inflammatory bowel disease in children with abdominal pain and diarrhoea

Literature buzz Diagnostics

Calgranulin C (S100A12) takes the lead among IBD biomarkers

Expert opinion

Inflammatory bowel disease (IBD) refers to several related illnesses that affect the digestive tract, which becomes swollen and inflamed. Gut tissue can be broken or damaged. IBD leads to chronic, long-lasting inflammation or irritation of the stomach, small intestine and/or colon.
It is important to diagnose children and teenagers suffering from chronic abdominal pain and diarrhea as early as possible. Stool testing is now commonly established as one of the first paths for clinical investigation. However, endoscopy with tissue sample biopsy is still the definitive method for assessing inflammatory bowel disease and determining how much of the colon is involved. It is therefore critical to use the most predictive assay and the most trustable biomarker before proceeding with the endoscopy procedure.
This article evaluates two candidate biomarkers in stool tests: Calprotectin and Calgranulin C (S100A12). Using a well-stratified patient group of children and teenagers, Anke Heida and collaborators of the CACATU consortium performed an in-depth comparison of the two biomarkers in a well-designed clinical study.
While both markers have excellent test characteristics for predicting IBD, Calgranulin C (S100A12) does demonstrate significantly better specificity.
When you have the choice, why not pick the most effective?

Abstract

Calgranulin-C (S100A12) is a new fecal marker of inflammation that is potentially more specific for inflammatory bowel disease (IBD) than calprotectin, since it is only released by activated granulocytes. We compared calgranulin-C and calprotectin to see which of the two tests best predicted IBD in children with chronic abdominal pain and diarrhea.
Previously undiagnosed patients aged 6-17 years, who were seen in pediatric clinics in the Netherlands and Belgium, sent in a stool sample for analysis. Patients with a high likelihood of IBD underwent upper and lower endoscopy (ie, preferred reference test), while those with a low likelihood were followed for 6 months for latent IBD to become visible (ie, alternative reference test). We used Bayesian modelling to correct for differential verification bias.
Primary outcome was the specificity for IBD using predefined test thresholds (calgranulin-C: 0.75 µg/g, calprotectin: 50 µg/g). Secondary outcome was the test accuracy with thresholds based on receiver operating characteristics (ROC) analysis.
IBD was diagnosed in 93 of 337 patients. Calgranulin-C had significantly better specificity than calprotectin when predefined thresholds were used (97% (95% credible interval (CI) 94% to 99%) vs 71% (95% CI 63% to 79%), respectively). When ROC-based thresholds were used (calgranulin-C: 0.75 µg/g, calprotectin: 400 µg/g), both tests performed equally well (specificity: 97% (95% CI 94% to 99%) vs 98% (95% CI 95% to 100%)).
Both calgranulin-C and calprotectin have excellent test characteristics to predict IBD and justify endoscopy.

Details

Archive of Disease in Childhood. 2018 Mar 7; 0; 1-7. doi: 10.1136/archdischild-2017-314081.

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