Fecal Immunochemical Test
Immunochemical fecal occult blood test; Immunological fecal occult blood test; iFOBT; Fecal occult blood test; FIT
Fecal immunochemical tests (FIT) incorporate an antibody specific for human hemoglobin; such react with the globin protein moiety of hemoglobin.
Fate of Hemoglobin in the Gastro-Intestinal Tract
The globin moiety of hemoglobin is a protein and as such is rapidly digested in stomach or small intestine such that it is no longer detectable by immunochemical methods. Ingestion of blood volumes of up to 100 mL has not resulted in detectable immunoreactive hemoglobin in feces, based on reports using some of the earlier types of FIT. In other words, FIT are selective for colorectal