Studies of carcinoembryonic antigen activity of whole and extracted serum in ulcerative colitis.

The present study has used a microradioimmunoassay to detect carcinoembryonic antigen(s) (CEA) in whole and extracted serum in 77 patients with ulcerative colitis, two of whom had coexisting colonic carcinoma, and 69 patients with carcinoma of the colon or rectum. Taking 5 ng/ml as the level of positivity, the CEA assay on whole serum showed positive results in patients with ;active' ulcerative colitis (15 of 17) but not in those with ;inactive' disease (0 of 23). In two patients, levels fell during drug-induced remission. Our results also indicated that a positive result for CEA on extracted serum was associated with carcinomatous changes in ulcerative colitis in contrast to uncomplicated ulcerative colitis in which positive results were obtained only with whole serum.