Carcinoembryonic Antigen (CEA)
Other marker
CEA
Carcinoembryonic Antigen (CEA)
A glycoprotein produced in fetal gut tissue and present at low levels in healthy adults. It is used mainly as a tumour marker for colorectal cancer, where it helps monitor treatment response and detect recurrence, and can also rise with several other cancers and with benign conditions.
PED Notes
Not a PED-specific marker, but it appears on broad screening panels that athletes sometimes order. The single most important interpretive point for this group is smoking: cigarette smokers have higher baseline CEA, so the non-smoker cutoff (about 3 ng/mL) should be relaxed to roughly 5 ng/mL in smokers. CEA is a monitoring tool, not a screening test for healthy people, and mild elevations are far more often benign (smoking, inflammation, liver or lung disease) than malignant.
When high
When elevated:
- First account for smoking, which raises baseline CEA; the non-smoker reference is about <3 ng/mL and the smoker reference about <5 ng/mL
- Mild elevations are commonly benign: smoking, chronic inflammation, benign liver disease, peptic ulcer, COPD; recheck and correlate with the clinical picture
- CEA is chiefly valuable for tracking a known colorectal cancer (falling with successful treatment, rising with recurrence); it is a poor standalone screening test and should not be used to diagnose cancer in an asymptomatic person
- A persistently rising CEA without an obvious benign cause warrants gastroenterology/oncology evaluation (colonoscopy, imaging)
Action: Do not panic over a mild isolated elevation. Stop smoking (which will often lower it), repeat the test, and pursue formal workup only if it stays elevated or climbs.
History Chart
Reading History
Frequently Asked Questions
Reference Ranges
Standard Range