Carcinoembryonic antigen (CEA)

Carcinoembryonic antigen (CEA) is a protein normally found in very low levels in the blood of adults. The CEA blood level may be increased in certain types of cancer and non-cancerous (benign) conditions. A CEA test is most commonly used for colorectal cancer.

Why a CEA test is done

A CEA test may be done:

  • if the doctor suspects there may be cancer
  • to find out if cancer treatment is working
  • to find out if cancer has come back (recurred) after treatment

How a CEA test is done

A CEA test is usually a blood test that measures the amount of CEA protein in the blood. A sample of blood is taken by inserting a needle into the vein in your arm. No special preparation is needed.

What the results mean

An increased CEA value can occur in both cancers and non-cancerous conditions.


The CEA blood levels are often increased in colorectal cancer and may be increased in other cancers including:

  • breast
  • lung
  • pancreatic
  • stomach
  • liver
  • ovarian

After treatment, a return to a normal CEA level that had been elevated usually means that the cancer has responded to treatment.

A CEA level that rises steadily after treatment is complete often means that the cancer has come back (recurred).

Non-cancerous conditions

The CEA blood level may be increased in non-cancerous conditions including:

  • a peptic ulcer
  • ulcerative colitis
  • rectal polyps
  • emphysema
  • benign breast disease
  • an inflammation such as pancreatitis (inflammation of the pancreas) or cholecystitis (inflammation of the gallbladder)

Smokers who do not have cancer can also have an increased CEA value.

What happens if the result is abnormal

The doctor will decide whether further tests, procedures, follow-up care or additional treatment are needed.

Expert review and references

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

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