Carcinoembryonic Antigen

Does this test have other names?

CEA

What is this test?

This test measures a protein called carcinoembryonic antigen (CEA) in your blood. This protein is found on some types of cancer cells.

CEA is called a tumor marker because it gives information about cancer in your body. This test may help your doctor find out if your cancer treatment is working. It may also help your doctor know if the cancer is coming back after treatment. The test can be used with cancers of the colon and rectum, lung, breast, pancreas, ovary, prostate, liver, and thyroid.

Your doctor cannot tell what type of cancer you have based on this test. Because CEA can be present in conditions that aren't cancer and may not be present for all cancers, this test isn't usually used for cancer screening.

Why do you need this test?

You may need this test if you have already been diagnosed with cancer and your doctor is planning treatment. CEA can help your doctor know more about your cancer before treatment begins.

You may have this test during cancer treatment to help your doctor know how well the treatment is working.

If you have already been treated for cancer, you may need this test to help find out whether your cancer has come back.

What other tests might you have along with this test?

Your doctor may order other tests to find out more about your cancer. These may include X-rays, CT scans, PET scans, and biopsies.

What do your test results mean?

Test results may vary depending on your age, sex, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your doctor what your test results mean for you.

CEA is measured in nanograms per milliliter (ng/mL). Normal results are 2.5 ng/mL or lower in nonsmokers.

But having a normal CEA level doesn't rule out cancer. Some people with cancer have a normal CEA.

And higher levels of CEA don't mean you have cancer. Many conditions other than cancer can cause CEA to go up. These include:

• Infections.

• Liver disease.

• Ulcers.

• Breast cysts.

• Lung problems.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect your test results?

Being pregnant or being a smoker can raise your CEA levels. A CEA of up to 5.0 ng/mL can be considered normal in smokers.

How do you get ready for this test?

You don't need to prepare for this test. Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.