Intestinal protein loss and bleeding assessed by fecal hemoglobin, transferrin, albumin, and alpha-1-antitrypsin levels in patients with colorectal diseases.

Four fecal proteins (hemoglobin, transferrin, albumin, and alpha 1-antitrypsin) were measured by enzyme-linked immunosorbent assay (ELISA) in patients with colorectal diseases. Levels of all 4 proteins were significantly increased in patients with colonic cancer and ulcerative colitis (UC) compared to levels in control subjects, while fecal alpha 1-antitrypsin was particularly elevated in colonic Crohn's disease (CD). That is, the fecal protein pattern of CD was distinct from those of colonic polyps, colonic cancer, and UC. To investigate whether levels of these fecal proteins reflect disease activity in UC and CD, comparative evaluation of fecal proteins in the active and inactive phases was performed. In UC, differences in the fecal concentrations of all 4 proteins were significant between the active and inactive phases of the disease. In CD, however, the difference in alpha 1-antitrypsin concentration was significant. Our results suggest that measurements of these 4 fecal proteins would be useful in the screening of colorectal diseases. In addition, these markers can also be used as indicators of disease activity in inflammatory bowel diseases.