The Colon Mucus Test in Comparison with the Fecal Occult Blood Test in the Detection of Gastrointestinal Disease

Abstract: This study was undertaken to assess the diagnostic significance of the colon mucus test (CMT) by which the cancer‐associated carbohydrate antigen, β‐D‐Gal (1 ‐ 3)‐D‐GalNAc (T antigen) is measured in rectal mucus, chiefly in patients with various alimentary tract diseases. The incidence of a positive CMT was relatively high in colorectal cancer (69%) and gastric cancer (40%), and was similarly high in some benign colorectal diseases such as colonic diverticulum (42%) and colonic polyps (39%), and in gastric polyps (75%). On the other hand, the incidence of a positive CMT in other benign diseases or in healthy controls was less than 10%. A positive CMT was significantly more common in colorectal disease and in gastric tumors (cancer and polyps) than in the other diseases (p < 0.001). Of 28 colonic polyp patients, 20 (71%) had negative fecal occult blood test results (FOBT), and nine of them (45%) had positive CMT results. These results suggest that the CMT may be a useful screening test for alimentary tract disease, particularly colorectal disease and gastric tumors, although its specificity for colorectal cancer is only moderate. Furthermore, a combination assay using FOBT plus CMT may help to improve the diagnostic rate.