Background: Gastrointestinal (GI) bleeding can result from various conditions, including ulcers, neoplasms and infectious enterocolitis. The aim of this study was to evaluate the utility of the fecal immunochemical transferrin test compared with the fecal Hb test in various clinical settings.

Methods: A total of 1,116 clinical stool specimens submitted for fecal occult blood testing were prospectively examined using both FIT Hb and FIT Tf kits (AlfresaPharma, Japan). To verify the specificity of the two tests, stool specimens from 265 health check-up examinees were also included.

Results: A review of medical records revealed that 396 patients had clinical conditions associated with GI bleeding. FIT Hb and FIT Tf results were positive in 156 (39.4%) and 137 (34.6%) cases, respectively, and an additional 194 (49.0%) cases tested positive with either FIT Hb or FIT Tf. The two tests showed a moderate strength of agreement (kappa value; 0.56). Colitis (n=71) was associated with the most GI bleedings, followed by acute gastroenteritis (n=29), GI ulcers (n=27) and GI cancers (n=15). While the first two groups had higher positive rates on FIT Tf, patients in the latter two groups had higher positive rates on FIT Hb. Notably, four of nine specimens from premature babies tested positive only on FIT Tf. The specificity of FIT Hb and FIT Tf was 100% and 99.6%, respectively.

Conclusion: Concurrent use of FIT Hb and FIT Tf improved the detection rate of occult GI bleeding, especially in patients with infectious GI disease (such as colitis or gastroenteritis) and in premature babies. (Ann Clin Microbiol 2018;21:51-57)