Carcinoembryonic Antigen (CEA) Test

The CEA test measures the level of carcinoembryonic antigen, a protein that is normally present at very low levels in adults but can be elevated in certain cancers and inflammatory conditions. It is most commonly used as a tumor marker in the evaluation and monitoring of colorectal cancer.

What this test evaluates

• Blood concentration of CEA (ng/mL)

• Tumor-related antigen activity, particularly from gastrointestinal sources

Why a CEA test is ordered

• Baseline and follow-up monitoring in people with a history of colorectal cancer

• Detection of recurrence or progression after surgery, chemotherapy, or radiation

• Assessment of treatment response

• Supportive evaluation when symptoms or imaging raise concern for malignancy

How CEA levels are interpreted

• CEA is not cancer-specific

• Elevated levels can be seen with:

  • Colorectal cancer

  • Other cancers (gastric, pancreatic, lung, breast)

  • Smoking

  • Inflammatory bowel disease

  • Liver disease

  • Pancreatitis or infection

• For this reason, CEA is not used as a screening test in healthy individuals

What results may show

• Low or stable CEA: generally reassuring, especially when consistent over time

• Rising CEA trend: may suggest recurrence or active disease and usually prompts further evaluation

• Isolated mild elevation: often nonspecific; trend and context are key

Specimen requirements

• Blood draw

• Smoking can elevate CEA and should be disclosed when interpreting results

Clinical notes

• CEA is most valuable when compared against a patient’s own prior baseline

• Serial measurements are more informative than a single value

• Results should be interpreted alongside imaging, clinical findings, and other labs

After ordering, you will receive a LabCorp requisition with instructions for blood collection at a participating laboratory.

The CEA test is a practical tool for cancer surveillance and treatment monitoring rather than diagnosis on its own.