No fasting required.

Carcinoembryonic antigen (CEA) is a protein that is primarily associated with certain types of cancer. The most common way to measure CEA is through a blood test, although other bodily fluids may be tested as well.

CEA testing is not used to diagnose cancer, but it may assist doctors in predicting how a person’s cancer may be likely to progress, determining treatment effectiveness, and assessing whether or not cancer has returned after treatment.