Fecal Occult Blood(FOB) Rapid test is an in vitro diagnostic test for the qualitative detection of fecal occult blood (FOB).Fecal occult blood (FOB) examination is of great value in the diagnosis of gastrointestinal bleeding. I t is used as an auxiliary diagnosis for gastrointestinal bleeding caused by gastrointestinal diseases such as colon polyps, colorectal cancer, ulcerative colitis, and Crohn's virus.