Who gets for testing cea (carcinoembryonic antigen)?

Certain cancers: Cea (carcinoembryonic antigen) can be found at elevated levels in the blood of patients with certain cancers such as colon, lung, breast. It is useful to follow if elevated at the time of diagnosis to correlate with response (if it goes down) to treatment or with relapse (if it becomes elevated again after having gone down to normal levels previously). It may be elevated in other benign conditions.