Carcinoembryonic antigen (CEA) test
A carcinoembryonic antigen (CEA) test measures the amount of CEA in the blood.
CEA is a protein normally found in the tissue of a developing fetus. Everyone is born with high levels of this protein, and levels decrease after birth. Most healthy adults have very low levels of CEA in their blood.
But sometimes CEA levels can be higher than normal, such as when a person has certain non-cancerous (benign) conditions. They can also be higher when certain types of cancer are present in the body. A CEA test is most commonly used during treatment for colorectal cancer. It is sometimes used for other cancers.
Why a CEA test is done
Doctors mainly use CEA tests to check if cancer is responding to treatment or to see if it has come back (recurred) after treatment. They will use this test to measure CEA levels in the blood before, during and after treatment.
People who have cancer don’t always have high CEA levels, so this test can't be used to diagnose cancer or to check for signs of cancer before symptoms start. CEA levels can also be higher than normal with non-cancerous conditions, such as inflammatory bowel disease.
How a CEA test is done
A CEA test is a blood test. A lab technologist or nurse uses a needle to take a sample of blood from a vein in your arm.
The test is often done at a lab or a hospital. You usually don’t need to do anything to prepare for it.
What the results mean
These types of cancer can increase the level of CEA in the blood:
- colorectal
- breast
- lung
- pancreatic
- thyroid
- ovarian
The following non-cancerous conditions can also increase the level of CEA:
- inflammatory bowel disease
- a peptic ulcer (sores in the lining of the stomach or duodenum)
- pancreatitis (inflammation of the pancreas)
- cholecystitis (inflammation of the gallbladder)
- hepatitis (inflammation of the liver)
- chronic obstructive pulmonary disease (COPD), which is long-term damage to the lungs
-
diverticulitis
People who smoke tobacco who do not have cancer can also have higher levels of CEA.
If your healthcare team is using CEA tests to check if treatment for cancer is working, they will compare the CEA level before, during and after treatment. If the CEA level decreases or returns to normal, it may mean that the cancer is responding well to treatment. If the CEA level increases, it may mean that the cancer is still growing or has come back.
Talk to your healthcare team about what your results mean. Your doctor may recommend other tests or procedures, treatment or follow-up care.
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