2012, pp 1387-1389

Fecal Immunochemical Test

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Synonyms

Fecal occult blood test; FIT; iFOBT; Immunochemical fecal occult blood test; Immunological fecal occult blood test

Definition

A fecal immunochemical test for hemoglobin is a test designed to detect hemoglobin in feces using an antibody raised against human hemoglobin. It is one of a class of technologies referred to as fecal occult blood test (FOBT).

Characteristics

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 Gastrointestinal 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 bleeding, espec ...