From the Guidelines
Calprotectin has a sensitivity of approximately 78% and a specificity of 57% for detecting intestinal inflammation at a cutoff of 50 mg/g, as reported in the most recent study 1. The sensitivity and specificity of calprotectin vary depending on the cutoff threshold used, with higher cutoff values generally increasing specificity but decreasing sensitivity.
- At a cutoff of 50 mg/g, the sensitivity is 78% and specificity is 57% 1.
- At a cutoff of 150 mg/g, the sensitivity is 71% and specificity is 69% 1.
- At a cutoff of 250 mg/g, the sensitivity is 67% and specificity is 73% 1. It's essential to consider the clinical context and laboratory method employed when interpreting calprotectin results, as the test performance can be influenced by various factors, including disease extent and inter-individual heterogeneity in biomarker responsiveness 1. The use of calprotectin as a biomarker for gastrointestinal inflammation should be guided by downstream implications, including the risk of consequent treatment decisions, and test performance thresholds may vary depending on the specific clinical scenario 1. Overall, calprotectin is a useful tool for detecting intestinal inflammation, particularly in inflammatory bowel disease (IBD), but its performance characteristics should be carefully considered in the context of individual patient care.
From the Research
Sensitivity and Specificity of Calprotectin
- The sensitivity and specificity of calprotectin in diagnosing active inflammatory bowel disease (IBD) were found to be 85% and 75%, respectively, in a meta-analysis of 25 studies 2.
- A sub-group analysis revealed that calprotectin performed better in ulcerative colitis (UC) than in Crohn's disease (CD), with pooled sensitivity and specificity of 87.3% and 77.1% in UC, and 82.4% and 72.1% in CD 2.
- Another study found that the sensitivity and specificity of calprotectin for diagnosis of IBD were 82-83% and 84-89%, respectively, using six different calprotectin assays 3.
- A systematic review and meta-analysis of 19 studies found that the pooled sensitivity and specificity estimates for calprotectin were 0.88 and 0.73, respectively, in assessing endoscopically defined disease activity in IBD 4.
- The optimum calprotectin cut-off levels for achieving the best sensitivity and specificity were found to be 50 μg/g and >100 μg/g, respectively 2.
- Calprotectin was found to be more sensitive than C-reactive protein (CRP) in both UC and CD, and more sensitive in UC than CD 4.
Comparison with Other Biomarkers
- Calprotectin was compared with CRP and stool lactoferrin (SL) in a systematic review and meta-analysis, and was found to have higher sensitivity and similar specificity to SL, but higher sensitivity and lower specificity than CRP 4.
- The diagnostic accuracy of calprotectin was found to be comparable to that of other biomarkers, such as CRP and SL, in assessing endoscopically defined disease activity in IBD 4.
Clinical Applications
- Calprotectin has been found to be a useful non-invasive marker for intestinal inflammation, and can be used to differentiate between organic and functional disease 5.
- Calprotectin can be used to monitor disease activity and predict treatment response in IBD patients, with an excellent correlation with endoscopic activity 5.
- The role of calprotectin in collagenous colitis and infectious colitis is less clear and still under investigation 5.