what is a normal cea
CEA is a protein marker indicative of several types of cancers, especially colon cancer. The CEA normal levels are different for smokers and nonsmokers. Usually, for adult nonsmokers, the normal CEA levels range from 0 to 2.5 mcg/l.For adult smokers, the levels are slightly higher, and normal levels range from 0 to 5.0 mcg/l. This difference in normal values is because smokers usually produce more CEA than nonsmokers.he CEA test is performed to monitor the severity of cancer or tumors in the patients. The values obtained after the CEA test indicates the response of body to the therapy. So, CEA values are used as a marker mainly for colon cancer.