Clinical Summary

Carcinoembryonic antigen (CEA) comprises a heterogeneous family of glycoproteins ranging in weight from 175,000 to 200,000 daltons due to varying carbohydrate and amino acid content. Its biological function is not well defined, but it may play a role in intercellular recognition, regulation of the immune response, and metastasis of colorectal cancer.  The name derives from the previous belief that CEA occurred only in gastrointestinal carcinomas and the fetal digestive tract. Elevated levels have since been detected in a number of malignant and nonmalignant conditions of the gastrointestinal tract and other sites. These conditions include various hepatic diseases; inflammatory lesions, particularly of the gastrointestinal tract; infections; trauma; infarction; collagen vascular disease; renal impairment; and smoking (current and past).