The combined detection had higher sensitivity than single detection, with statistically significant differences compared to serum-based detection (p < 0.001).<h4>Conclusion</h4>Combining fecal mSDC2 with serum CEA and CA72-4 increased sensitivity for CRC detection in this single-center study, at the cost of reduced specificity. The gene discussed is CEACAM5; the disease is colorectal carcinoma.