Carcinoembryonic Antigen (CEA)

Test Overview

The carcinoembryonic antigen (CEA) test measures the amount of this protein that may appear in the blood of some people who have certain kinds of cancers, especially large intestine (colon and rectal) cancer. It may also be present in people with cancer of the pancreas, breast, ovary, or lung.

CEA is normally produced during the development of a fetus. The production of CEA stops before birth, and it usually is not present in the blood of healthy adults.

Why It Is Done

The carcinoembryonic antigen (CEA) test is used to:

  • Find how widespread cancer is for some types of the disease, especially colon cancer.
  • Check the success of treatment for colon cancer.
    • CEA levels may be measured both before and after surgery to evaluate both the success of the surgery and the person's chances of recovery.
    • CEA levels may be measured during treatment with medicines to destroy cancer cells (chemotherapy). This provides information about how well the treatment is working.
  • Check to see if cancer has returned after treatment.

How To Prepare

You do not need to do anything before you have this test.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .

How It Is Done

The health professional taking a sample of your blood will:

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Attach a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure to the site and then put on a bandage.

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Risks

There is very little chance of a problem from having blood drawn from a vein.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
  • Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

The carcinoembryonic antigen (CEA) test measures the amount of this protein that may appear in the blood of some people who have certain kinds of cancers, especially large intestine (colon and rectal) cancer. It may also be present in people with cancer of the pancreas, breast, ovary, or lung.

Results are usually available in 1 to 3 days.

Normal

Normal values may vary from lab to lab.

Carcinoembryonic antigen

Nonsmokers:

2.5–5 nanograms per milliliter (ng/mL) or 2.5–5 micrograms per liter (mcg/L).

Smokers:

Up to 5 ng/mL or 5 mcg/L

Many conditions can change your CEA levels. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and medical history.

Most cancers do not produce this protein, so your CEA may be normal even though you have cancer.

High values

  • Cancer of the colon, lung, pancreas, breast, or ovary may be present.
  • Cancer may not be responding to treatment.
  • Cancer may have returned after treatment. A steadily rising CEA may be the first sign that cancer has come back after treatment. Also, people with advanced cancer or cancer that has spread to other parts of the body (metastatic cancer) may have high CEA levels if their original cancer produced this protein before treatment.
  • Another condition or disease is present, such as cirrhosis, pancreatitis, kidney failure, inflammatory bowel disease, peptic ulcer disease, chronic obstructive pulmonary disease (COPD), or an obstructed bile duct.

Low values

  • People with small cancers or early-stage disease usually have low, or even normal, CEA levels.

What Affects the Test

Heavy smoking affects the test results.

What To Think About

  • The CEA blood test is not reliable for diagnosing cancer or as a screening test for early detection of cancer.
  • CEA testing is a reliable test for recurrent colon cancer if the original cancer produced this protein before treatment.
  • Most types of cancer do not produce a high CEA. Having a normal CEA level does not mean that you do not have cancer.
  • CEA levels usually return to near-normal levels within 6 weeks of starting treatment if cancer treatment is successful.
  • Measuring the amount of CEA in other body fluids, such as abdominal fluid (peritoneal fluid) or the fluid around the brain and spinal cord (cerebrospinal fluid, or CSF), can determine whether cancer has spread to that part of the body.
  • Other diseases, such as COPD, cirrhosis, and Crohn's disease, may also raise CEA blood levels.
  • CEA levels are usually higher in smokers than in people who do not smoke.

References

Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2006). Mosby’s Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis: Mosby.

Credits

Author Bets Davis, MFA
Editor Maria Essig
Associate Editor Tracy Landauer
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
Last Updated April 29, 2009

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