Carcinoembryonic Antigen (CEA)
Monitor Cancer Treatment with a Private CEA Blood Test
The Carcinoembryonic Antigen (CEA) blood test measures the level of CEA, a protein that may be produced by certain cancers. It is most commonly used to monitor patients who have already been diagnosed with cancer, assess how well treatment is working, and help detect possible recurrence after treatment.
Although CEA is often associated with colorectal (bowel) cancer, elevated levels may also occur in other cancers and several non-cancerous conditions. For this reason, the test should always be interpreted alongside your medical history, symptoms, imaging, and other laboratory investigations.
Important: A CEA blood test cannot diagnose or exclude cancer on its own. It is a valuable tumour marker that supports clinical decision-making but should never be used as a standalone diagnostic test.
What is Carcinoembryonic Antigen (CEA)?
Carcinoembryonic Antigen (CEA) is a glycoprotein normally produced during foetal development. After birth, production falls to very low levels, meaning healthy adults typically have only small amounts circulating in the bloodstream.
Some cancer cells begin producing CEA again as they grow. This allows clinicians to measure CEA in a blood sample and use it as a tumour marker.
Rather than diagnosing cancer, CEA is primarily used to monitor changes over time, helping clinicians evaluate whether treatment is working or whether further investigations may be required.
Why Might a Doctor Request a CEA Blood Test?
A CEA blood test may be recommended to:
- Monitor treatment response in patients with known cancer.
- Detect possible cancer recurrence after surgery or chemotherapy.
- Support the assessment of disease progression.
- Establish a baseline before treatment begins.
- Monitor CEA levels over time using serial blood tests.
Repeated measurements are often far more informative than a single result, as trends can provide valuable clinical information.
Which Cancers Can Produce Elevated CEA?
CEA may be elevated in several cancers, including:
| Cancer | Clinical Use of CEA |
|---|---|
| Colorectal (Bowel) Cancer | Most established use for monitoring treatment and recurrence. |
| Pancreatic Cancer | May assist monitoring alongside imaging and other tumour markers. |
| Stomach (Gastric) Cancer | Sometimes used during follow-up. |
| Lung Cancer | May be used in selected patients. |
| Breast Cancer | Occasionally monitored in advanced disease. |
| Ovarian Cancer | May be used alongside other tumour markers in selected cases. |
| Medullary Thyroid Cancer | Can contribute to clinical assessment in combination with other markers. |
Not every cancer produces CEA, and not every patient with cancer will have an elevated CEA level.
Non-Cancer Causes of Raised CEA
An elevated CEA result does not automatically mean cancer is present.
CEA levels may also increase due to:
- Smoking
- Chronic liver disease
- Cirrhosis
- Pancreatitis
- Diverticulitis
- Inflammatory bowel disease (Crohn's disease or ulcerative colitis)
- Chronic lung disease
- Benign gastrointestinal disorders
Your healthcare professional will interpret your result in the context of your overall health.
How Does CEA Monitoring Work?
Unlike many routine blood tests, the trend of CEA is often more important than a single measurement.
For example:
- A falling CEA level after treatment may suggest a positive response.
- Stable CEA levels may indicate disease stability.
- A steadily rising CEA level may prompt further investigations such as imaging or additional laboratory testing.
For this reason, clinicians often compare your current result with previous CEA measurements.
When Is a CEA Test Appropriate?
A CEA blood test may be appropriate if you:
- Have previously been diagnosed with colorectal cancer.
- Are receiving treatment for certain cancers.
- Have completed cancer treatment and require follow-up monitoring.
- Have been advised by your clinician to monitor tumour marker levels.
- Require additional information alongside other investigations.
When Is a CEA Test NOT Recommended?
A CEA blood test is not recommended as:
- A routine cancer screening test for healthy individuals.
- A replacement for bowel screening programmes.
- A substitute for colonoscopy or medical imaging.
- A standalone test to diagnose cancer.
- A way of excluding cancer if symptoms are present.
If you have symptoms such as unexplained weight loss, persistent bowel changes, rectal bleeding, unexplained anaemia, or ongoing abdominal pain, you should seek medical assessment regardless of your CEA result.
Understanding Your Results
Low or Normal CEA
A normal CEA level is reassuring but does not completely exclude cancer. Some cancers produce very little or no CEA.
Raised CEA
An elevated CEA result does not necessarily indicate cancer.
Your clinician may recommend:
- Repeat CEA testing
- Additional blood tests
- CT or MRI imaging
- Colonoscopy or other investigations
- Referral to an appropriate specialist
Results should always be interpreted by a qualified healthcare professional.
Why Choose Marylebone Diagnostic Centre?
At Marylebone Diagnostic Centre, we combine high-quality laboratory diagnostics with experienced clinical care.
Our service includes:
- Central London location near Baker Street.
- Professional clinician-led blood collection.
- Fast turnaround time of 1–2 working days.
- Secure electronic results.
- Access to hundreds of specialist blood tests.
- Optional GP consultation for clinical interpretation.
- Comprehensive cancer marker testing.
Related Cancer Blood Tests
Depending on your clinical history, your healthcare professional may recommend additional tumour markers alongside CEA.
These may include:
The most appropriate tests depend on your symptoms, medical history, and the type of cancer being investigated or monitored.
Frequently Asked Questions
Important Clinical Information
The Carcinoembryonic Antigen (CEA) blood test is a valuable tumour marker used to support the monitoring of certain cancers. It is not intended to diagnose cancer or replace clinical assessment. Test results should always be interpreted alongside your medical history, symptoms, examination findings, imaging, and any additional laboratory investigations. If your result is abnormal, further assessment may be recommended by your healthcare professional.
Book Your Private CEA Blood Test
Located only a five-minute walk from Baker Street Underground Station, Marylebone Diagnostic Centre provides convenient access for patients across London and the surrounding areas. Results are available within 1–2 working days, with no GP referral required.
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