What it means
A protein made by some tissues before birth and by some cancers, especially colorectal cancer. A level is taken before treatment and then repeated: a falling level suggests treatment is working, and a rising level can mean the cancer has come back. It is not a screening test, because smoking, inflammation and liver disease can raise it in people without cancer, and some cancers do not raise it.
For the nurse
Ask about smoking and note it, since it raises the level. Explain that the trend over time matters more than one number.
At a glance
| Normal range | Below about 3 ng/mL [3 mcg/L] in nonsmokers; up to about 5 ng/mL [5 mcg/L] in smokers. Ranges vary by lab. |
|---|---|
| Also written | CEA |
Related terms
antineoplastic
A drug used to treat cancer by killing cancer cells or stopping them from growing and dividing.
CA-125
A blood test for cancer antigen 125, a protein used as a tumor marker for ovarian cancer.