Carcinoembryonic Antigen

A carcinoembryonic antigen (CEA) test is a blood test used to help diagnose and manage certain types of cancers. The CEA test is used especially for cancers of the large intestine and rectum. You doctor can also use the test results to help determine if a cancer treatment is working.

An antigen is a substance that’s made by cancerous tumour cells. Sometimes antigens are released into the bloodstream. The CEA test measures the amount of CEA in the blood. A high amount of CEA in your body after a cancer treatment or surgery suggests the cancer is not gone. It may also mean that the cancer has spread to other parts of your body. Smoking can increase the amount of CEA in your body even in the absence of cancer.

The CEA test has different uses. Your doctor can order a CEA test if your symptoms suggest you might have cancer. A CEA test can help your doctor find out if a cancer treatment is working. These treatments may have included surgery, chemotherapy, radiation, or a combination of all three. Your doctor might also use the CEA test to help determine if a cancer has come back, or recurred, after finishing treatment.

A CEA test is most useful after a diagnosis of a type of cancer that’s known to produce CEA. Not all cancers produce CEA.

Increased levels of CEA may be found in the following cancers:

•       colorectal or colon cancer
•       medullary thyroid carcinoma
•       breast cancer
•       cancer of the gastrointestinal tract
•       liver cancer
•       lung cancer
•       ovarian cancer
•       pancreatic cancer
•       prostate cancer

Cause levels higher than 3 ng/mL. These can include:

•       infection
•       cirrhosis
•       chronic smoking
•       inflammatory bowel disease (IBD)

What are normal CEA levels?

A normal level of CEA is less than or equal to 3 nomograms per millilitre (ng/mL). Most healthy people have levels below this amount. CEA levels will generally return to normal between one and four months after the cancer has been successfully removed.

What are abnormal CEA levels?

Elevated levels of CEA occur when the CEA is higher than 3 ng/mL. These levels are considered abnormal. People with many types of cancers can have levels that are higher than 3 ng/mL. If you have values that are that high, it doesn’t mean you have cancer.

CEA levels shouldn’t be the only test used to determine if you have cancer. Your doctor will use the CEA test along with other tests and an evaluation of your symptoms. You and your doctor can work together to decide your best treatment option if your doctor determines you have cancer.