Carcinoembryonic antigen 5.56ng/ml is on the high side, which does not mean that the condition is serious, and the specific cause of the disease needs to be diagnosed in detail. Carcinoembryonic antigen, also known as CEA, can be used as a tumor marker for colorectal cancer, breast cancer, lung cancer and other malignant tumors for auxiliary diagnosis. The normal value of carcinoembryonic antigen is below 5ng/ml, and 5.56ng/ml is just a little high, which may be caused by heavy smoking, or may indicate that the lesion is in an active stage, such as infection, inflammation, autoimmune disease, etc. If there are multiple serum tumors in the body at the same time, it is necessary to make a detailed diagnosis. If multiple serum tumor markers are elevated at the same time, the tumor should be investigated. When carcinoembryonic antigen (CEA) 5.56ng/ml is present, it should be judged in combination with specific clinical manifestations, medical history and imaging examination, etc. If you have been a smoker, it is recommended to quit smoking for a period of time and then check the CEA again, so as not to affect the result.