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Questions and answers

What does a high CEA in a blood test mean?

A high CEA does not always mean cancer: benign causes, correct use and next steps

Updated: 28 October 20261 min read4 references
Short answer

CEA is a substance released into the blood by both cancer cells and healthy cells. A high level may be a sign of bowel cancer or several other cancers, but it is also raised in smokers and in harmless conditions such as bowel inflammation, pancreatitis, stomach ulcers, liver disease and an underactive thyroid [1, 2]. CEA is not suitable for finding cancer in healthy people; its main use is to follow people who have already had bowel cancer [2, 4]. Review a high result with your doctor; usually the first step is an examination and a repeat test [2].

Key points

  • A CEA above 3 to 5 is usually considered "high"; it is naturally slightly higher in men, smokers and older people [2].
  • In patients with cancer, a high CEA before surgery is linked to a worse outcome, and if it does not fall after surgery, disease may remain or have come back [2].
  • In follow-up after bowel cancer treatment, regular CEA measurements show recurrence on average about 5 months earlier; they are most useful for finding spread to the liver [3].

Known causes of a raised CEA

GroupExamplesExplanation
HabitsSmokingNaturally higher in smokers [2]
Digestive diseasesStomach ulcer, bowel inflammation, pancreatitisBenign causes [2]
Liver diseasesCirrhosis, hepatitisBenign causes [2]
Other benign causesUnderactive thyroid, infections, benign breast conditionsBenign causes [2]
CancersBowel; lung, stomach, oesophagus, pancreas; some ovarian and cervical cancersCancer causes [2]

A single high value on its own is not enough to diagnose any disease.

Suggested approach to a high CEA in someone with no history of cancer

  1. 1

    History and examination

    The doctor asks about symptoms, smoking and liver and bowel conditions, and examines you [2].

  2. 2

    Repeat CEA and other tests

    CEA again, with a blood count, iron, and liver and kidney tests [2].

  3. 3

    If the CEA is below 10 and the examination is normal

    Repeat the test 3 months later [2].

  4. 4

    If the CEA is above 10

    Usually a CT or PET scan of the whole body [2].

When should I call my doctor?

In any case, discuss the result with your doctor. If you have symptoms such as blood in the stool, a change in bowel habit, unexplained weight loss or anaemia, see your doctor sooner.

If you have had bowel cancer and your CEA has risen during follow-up, contact your treatment team without delay; a CEA that does not return to normal or that rises can be a sign of recurrence [2].

Related questions

I smoke and my CEA is slightly high; should I worry?

CEA is naturally higher in smokers [2]. Even so, the final interpretation is your doctor's; based on your symptoms and examination, they will decide whether a repeat test is enough or more tests are needed.

My CEA is normal; does that mean I don't have bowel cancer?

Not necessarily. CEA is not much help in finding early bowel cancer [3]. For screening, use proven methods such as a stool test or colonoscopy (At what age is colonoscopy needed?).

After surgery for bowel cancer, how often should CEA be checked?

According to the American Society of Clinical Oncology guideline, in stage 2 and 3 every 3 months for at least 3 years, if surgery or chemotherapy would be suitable for you should the cancer come back [4]. Your treatment team sets the exact plan.

Related cancer types

Colorectal cancer

Related questions

Can cancer be prevented?My faecal occult blood test was positive. What should I do?At what age is a screening colonoscopy needed?Can I exercise during cancer treatment?Do red meat and processed meat cause cancer?Does alcohol cause cancer?Does obesity cause cancer?Does sugar make cancer grow?

References

4 references
Show all references, 2 with a study cardClose the reference list

Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.

  1. 1
    Colon Cancer Treatment (PDQ®)–Patient VersionNational Cancer Institute · cancer.gov
    Source Back to text
  2. 2
    A Review of the Role of Carcinoembryonic Antigen in Clinical PracticeHall C, Clarke L, Pal A, Buchwald P, Eglinton T, Wakeman C, et al · Ann Coloproctol · 2019;35:294-305
    Study cardDOI Back to text: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
  3. 3
    Carcinoembryonic Antigen as a Marker for Colorectal Cancer: Is It Clinically Useful?Duffy MJ · Clinical Chemistry · 2001;47:624-630
    DOI Back to text: 1 2
  4. 4
    ASCO 2006 Update of Recommendations for the Use of Tumor Markers in Gastrointestinal CancerLocker GY, Hamilton S, Harris J, Jessup JM, Kemeny N, Macdonald JS, et al · JCO · 2006;24:5313-5327
    Study cardDOI Back to text: 1 2

This page is based on reputable scientific sources and was last updated on 28 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.

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Related pages

19 October 2026 What is a tumour marker and when is it useful? A tumour marker is a substance in the blood or tissue that gives information about cancer; it is most useful for following treatment and recurrence, not for check-ups in healthy people. 26 October 2026 My faecal occult blood test was positive. What should I do? If your faecal immunochemical test (FIT) is positive, you need a colonoscopy. In Isfahan only 20% of these people had one, although a quarter of them had polyps or cancer. 20% People in Isfahan who had a colonoscopy after a positive test 28 October 2026 Do red meat and processed meat cause cancer? Processed meat (sausages, ham, salami, hot dogs) raises the risk of bowel cancer, and red meat probably does too. The increase in risk is small but grows with the amount eaten; limit red meat and eat very little processed meat.