The findings validate the performance of anti-Fn-IgA as a plasma marker to increase the diagnostic sensitivity for early detection of CRC, and indicate that the serum levels of anti-Fn-IgA, CEA and CA19-9 combined have a better diagnosis values for screening early stage of CRC than CEA and CA19-9 combined diagnosis. The gene discussed is CEACAM5; the disease is colorectal carcinoma.