Carcinoembryonic antigen is mainly examined by enzyme-linked immunosorbent assay and radioimmunoassay. Elevated carcinoembryonic antigen is commonly found in pancreatic cancer, gastric cancer, breast cancer, colorectal cancer, liver cancer, lung cancer, and urologic tumors. Carcinoembryonic antigen can be measured by enzyme-linked immunosorbent assay through blood tests. The normal value of carcinoembryonic antigen is no more than 5ng/mL or less if the test is taken in this way. Additionally, patients may be tested by radioimmunoassay, and the normal range of carcinoembryonic antigen values for this method is 10 to 25 μg/L. Carcinoembryonic antigen can be detected mainly by enzyme-linked immunosorbent assay and radioimmunoassay. Carcinoembryonic antigen can only be used as an auxiliary diagnostic basis, if the patient’s carcinoembryonic antigen is abnormal, the patient should go to the hospital for further examination in time.