The normal value for those taking a CEA, or carcinoembryonic antigen, blood test is 0 to 2.5 micrograms per liter, according to MedlinePlus. For smokers, the normal value range is 0 to 5 micrograms per liter.
The test does not directly identify cancer but can indicate its presence, explains MedlinePlus. It helps doctors monitor a patient's response to cancer treatment and signs of colon cancer. The value can indicate the presence of other cancers, including breast, colon, lung, pancreatic or thyroid cancer. A high CEA value can also occur from noncancerous factors, such as liver and gallbladder problems, lung infection, inflammation of the pancreas or stomach ulcers.