Fecal occult blood test (FOBT) is economical, non‐invasive, and widely used screening important method, while the results are susceptible to the influence of diet and drugs, and it can be detected only when the pathological tissue is bleeding.14 Carcinoembryonic antigen (CEA) is a widely used tumor marker, and most malignancies usually have a high concentration of CEA serum. Here, CEACAM5 is linked to neoplasm.