The combination of quantitative faecal occult blood test and faecal calprotectin is a cost-effective strategy to avoid colonoscopies in symptomatic patients without relevant pathology

Background: Faecal occult blood test (FOBT) has demonstrated effectiveness in colorectal cancer (CRC) screening. Faecal calprotectin (FC) has proven efficient for evaluating activity in inflammatory bowel disease (IBD), but its value in CRC detection is less established. Most symptomatic patients have benign pathologies, but still undergo colonoscopy in many settings.

Aims: To evaluate the diagnostic accuracy and cost-effectiveness of the combination of FOBT plus FC in symptomatic patients.

Methods: Patients who completed colonic investigations and returned stool samples, on which FOBT and FC were performed, were recruited prospectively. CRC, advanced adenoma, IBD and angiodysplasia were considered as relevant pathologies.

Results: A total of 404 patients were included, of whom 87 (21.5%) had relevant pathologies. Sensitivity and specificity were 50.6% and 69.6% for FOBT, 78.2% and 54.4% for FC. Negative predictive value (NPV) was 90.1% for FC and 86.9% for FOBT. NPV for the combination of FOBT and FC was 94.1%, with a sensitivity and specificity of 88.5% and 50.3%. The area under ROC (receiver operator curve) (AUC) was 0.741 for FOBT, 0.736 for FC and 0.816 for the combination. The total cost for visits and procedures was €233,016 (€577/patient). Using a combination of FOBT and FC as pre-endoscopic tool allows colonoscopies to be reduced by 39.4%, reducing total costs by 20.5%.

Conclusion: The combination of FOBT and FC has a better diagnostic accuracy compared with each test alone. Performing both tests before colonoscopy is a less costly and more effective strategy, reducing unnecessary procedures and complications.