What is Carcinoembryonic Antigen (CEA)?

Illustration of a Blood Test. Photo © A.D.A.M.

Question: What is carcinoembryonic antigen (CEA)?

How is CEA used during colon cancer treatment?


Carcinoembryonic antigen (CEA) is pronounced "car-sin-oh-em-bree-on-ick an-ti-jen". CEA is a protein that normally is produced by a developing baby during pregnancy. CEA typically is not produced in large quantities in healthy adults. However, some types of cancer can produce CEA too.

Cancers that can produce CEA include those of the colon, rectum, breast, ovary, pancreas, and lung.

If a person has a cancer that makes CEA, the blood levels of the protein can be measured with a simple blood test.

Blood measurements of CEA can be used to evaluate and manage colon cancer treatments. For example:

  • Blood levels of CEA may be checked before and after surgery to see how successful the surgery has been at removing the entire tumor.
  • CEA levels may be measured before, during, and after chemotherapy or radiation therapy to see how well the treatments are working. If CEA levels are not decreasing as expected, your doctor may try a different treatment that will be more effective for you.
  • CEA levels can be checked over time to see if a cancer has returned (recurred) after treatment.

What Do CEA Test Results Mean?

Normal blood levels of CEA typically range from 0 to 2.5 micrograms per liter (mcg/L) for non-smokers.

Smoking can raise CEA levels. For smokers, normal blood levels of CEA may be slightly higher.

They typically range from 0 to 5 mcg/L.

Normal values for CEA may vary slightly from lab to lab.

Most cancers do not produce CEA. This means that a normal CEA level does not mean you are cancer-free. Also, abnormal (high) CEA levels can be present in people without cancer.

Other, non-cancerous conditions that can increase CEA levels include cirrhosis and other liver disease, diverticulitis, blocked bile ducts, heavy smoking, chronic obstructive pulmonary disease (COPD), lung infections, pancreatitis, inflammatory bowel disease, stomach ulcers, kidney disease, and kidney failure.


CEA. Medline Plus.  https://medlineplus.gov/ency/article/003574.htm

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