The carcinoembryonic antigen (CEA) tumor marker test measures a protein common to particular types of cancer cells as well as to a developing fetus, according to MedicineNet.com. Levels below 2.5 nanograms per milliliter are normal for non-smokers, and levels below 5 nanograms per milliliter are normal for smokers.
CEA is a tumor marker that rises in the blood in the presence of certain cancers, particularly cancers of the large intestine and rectum, notes WebMD. It may also be elevated in cancers of the pancreas or lung, and in women, in breast or ovarian cancers.
The blood test may be done to determine how widespread a particular cancer is, explains WebMD. It may also be used to gauge prognosis, evaluate the efficacy of treatment or to determine whether a cancer has recurred.
Other conditions can also raise the level of CEA in the blood, adds Lab Tests Online. Generalized inflammation, emphysema and benign breast disease can all increase CEA levels, as can gastrointestinal conditions, such as ulcerative colitis, colon or rectal polyps, and ulcers. Chemotherapy and radiation therapy can also cause CEA levels to rise due to the release of CEA into the bloodstream as a result of cancer cell death, adds MedicineNet.com.