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Carcinoembryonic Antigen (CEA)


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 cancer of the 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.


The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Carcinoembryonic antigen1


Less than 5 nanograms per milliliter (ng/mL) or less than 5 micrograms per liter (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

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.

WebMD Medical Reference from Healthwise

Last Updated: May 29, 2013
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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