Carcinoembryonic Antigen (CEA) is a protein primarily found in developing fetus. However, it may reappear in the cells or serum of adults suffering from some particular types of cancers, such as colon, rectum, stomach, liver, esophagus, and pancreas. It is also performed in breast, lung, or prostate cancers.

A test needs to be performed to determine CEA level in the blood. The normal range of CEA is less than 2.5 ng/ml in an adult non smoker. However, the CEA level is greater than 5.0 ng/ml in an adult smoker. The CEA test is useful to determine the effectiveness of the treatment in colorectal cancer.

There are some conditions that can aggravate the CEA level. These conditions include infection, smoking, pancreatitis, inflammatory bowel disease, and tumors. Different types of cancers present in the colon and rectum raise the CEA level in the blood. Therefore, the CEA test is useful to monitor the effectiveness of treatment CEA-rich tumors.

If a person shows high CEA levels in blood before getting the therapy, it should drop to normal level after a successful treatment. A constant or rising CEA level suggests the recurrence of the cancer and also indicates the ineffectiveness of the treatment. Remember, chemotherapy and radiation therapy can also raise the CEA levels. Cigarette smoking causes the CEA level to rise dramatically.