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 healthcare provider find out if your cancer treatment is working. It may also help your provider 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 healthcare provider 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.
You may need this test if you have already been diagnosed with cancer and your healthcare provider is planning treatment. CEA can help your provider know more about your cancer before treatment begins.
You may have this test during cancer treatment to help your provider 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.
Your healthcare provider may order other tests to find out more about your cancer. These may include X-rays, CT scans, PET scans, and biopsies.
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
CEA is measured in nanograms per milliliter (ng/mL). Normal results are 3.0 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:
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
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.
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.
You don't need to prepare for this test. Be sure your healthcare provider 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.