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This is a test that measures CEA (carcinoembryonic antigen) which is produced by some cancer cells. As a tumour marker it is used to monitor treatment for cancer and to check that a treated cancer has not returned. It is most often used in cancers of the gastrointestinal (GI) tract such as bowel cancer, but also lung, breast and other cancers. Because different types of cancer and noncancerous conditions can cause high CEA levels the CEA test cannot be used to diagnose specific cancer or to screen healthy people for cancer. CEA is usually measured in the blood but other fluids such as peritoneal fluid from the abdomen are sometimes used.

Why get tested?

CEA (carcinoembryonic antigen) is found in very small amounts in the tissue of babies in the womb. By the time the baby is born, detectable levels in the blood have disappeared.  Healthy adults produce little or no CEA but levels are higher in people with chronic inflammatory conditions such as chronic liver disease, inflammatory bowel disease (IBD) such as ulcerative colitis and chronic lung disease.   When levels are very high, this is strongly suggestive of cancer.  

Because different types of cancer and noncancerous conditions can cause high CEA levels, the test can't be used to diagnose a specific type of cancer, nor can it show where a cancer is located.  CEA is used to monitor people after their treatment such as surgery, chemotherapy, or radiotherapy to check the progress of treatment and to make sure that the cancer has not recurred. An increase or decrease in CEA levels during treatment can help decide whether treatment is working effectively.  

CEA is most often used to monitor people with cancers of the gastrointestinal (GI) tract such as bowel (colorectal) cancer. It may be raised in other cancers, such as lung and breast. A CEA test is performed at the time of diagnosis when the level is taken as a baseline measurement so that future CEA levels taken during and after treatment can be compared. Someone with cancer can have CEA testing regularly for several years after receiving their initial treatment.

Not all cancers produce CEA and having a result within the given reference range does not guarantee that cancer (including types of cancer known to produce CEA) is not present. 

Having the test


Blood as well as other fluids such as peritoneal fluid from the abdomen.


Any preparation?


Your results

Reading your test report

The level of CEA in the blood does not accurately reflect tumour size, however on initial testing, people with smaller and early-stage tumours are likely to have low CEA levels, while people with more advanced tumours, or tumours that have spread throughout the body, are likely to have high CEA levels. When CEA levels return to normal after treatment, it means that the CEA-producing tumour has been removed. A steadily rising CEA level may be the first sign that the cancer has returned.

Reference intervals

Your results will be compared to reference intervals (sometimes called a normal range).

  • Reference intervals are the range of results expected in healthy people. 
  • When compared against them your results may be flagged high or low if they sit outside this range.
  • Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms.   It is important that you tell themeverything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

  • Why does this test need to be done?
  • Do I need to prepare (such as fast or avoid medications) for the sample collection?
  • Will an abnormal result mean I need further tests?
  • How could it change the course of my care?
  • What will happen next, after the test?

Any more to know?

Smoking can cause a slight increase in CEA levels (high normal levels).

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

Get further trustworthy health information and advice from healthdirect.

Last Updated: Thursday, 1st June 2023

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