Understanding the Carcinoembryonic Antigen (CEA) Test
Hearing that your doctor has ordered a tumour marker blood test can understandably cause concern. One of the more commonly requested tumour markers is the Carcinoembryonic Antigen (CEA) test. In my practice, I explain that while CEA can provide valuable clinical information, it is not a test used to diagnose cancer on its own.
Instead, it is most often used to monitor certain cancers after diagnosis or treatment, alongside other clinical assessments and investigations.
What Is CEA?
CEA is a protein that is produced in very small amounts in healthy adults. However, levels may increase in certain cancers and some non-cancerous medical conditions.
The CEA blood test measures the amount of this protein circulating in your bloodstream.
Why Might Your Doctor Request a CEA Test?
Your doctor may recommend a CEA test to:
- Monitor treatment response in certain cancers
- Detect possible recurrence after cancer treatment
- Assist in the overall assessment of specific medical conditions
- Monitor disease progression in selected patients
CEA is not recommended as a routine screening test for the general population.
Which Cancers May Be Associated with Elevated CEA?
Higher CEA levels may be seen in some patients with:
- Colorectal cancer
- Lung cancer
- Breast cancer
- Pancreatic cancer
- Stomach cancer
- Ovarian cancer (in some cases)
However, not everyone with these cancers has an elevated CEA level.
Can CEA Be Elevated Without Cancer?
Yes. CEA levels can also increase due to several non-cancerous conditions, including:
- Smoking
- Liver disease
- Inflammatory bowel disease
- Pancreatitis
- Certain lung conditions
For this reason, an elevated CEA level does not automatically mean someone has cancer.
Can CEA Diagnose Cancer?
No.
This is one of the most common misconceptions I discuss with patients. A CEA test alone cannot diagnose or exclude cancer. Your doctor will interpret the result alongside your medical history, symptoms, physical examination, imaging studies and, when necessary, tissue biopsy.
When Should You Discuss CEA Testing with Your Doctor?
CEA testing may be appropriate if:
- You are undergoing treatment for certain cancers
- Your doctor is monitoring for cancer recurrence
- You have previously had elevated CEA levels requiring follow-up
- Your specialist recommends tumour marker monitoring
Routine CEA testing is generally not recommended for healthy individuals without symptoms or specific clinical indications.
Doctor's Insight
In my practice, I encourage patients not to interpret a single blood test result in isolation. The CEA test is a useful monitoring tool in selected situations, but it is only one part of a much larger clinical picture. If your doctor recommends this test, it is important to discuss what the result means in the context of your overall health and treatment plan.
– Dr. Teh Boon Teong
Consultant in Internal Medicine
Evercare Medical Care Centre, Penang, Malaysia.
Frequently Asked Questions
It measures the level of Carcinoembryonic Antigen, a protein that may be elevated in certain cancers and some non-cancerous conditions.
No. CEA cannot diagnose cancer on its own and should not be used as a standalone screening test.
Yes. Smoking is one of several non-cancerous factors that can cause elevated CEA levels.
It is commonly used to monitor treatment response or follow up after treatment for certain cancers.
Your doctor will interpret the result alongside your symptoms, medical history and any additional tests that may be required.