Fecal Occult Blood (FOB)-Transferrin Rapid Test Device is a one-step chromatographic immunoassay for the qualitative determination of human hemoglobin (Hb) and human transferrin (Tf) in stool samples to detect gastrointestinal bleeding. The test is intended for use by health care professionals as an aid in the diagnosis of premature syndrome linked to the intestinal bleeding.

Colorectal cancer is a leading cause of illness and death in the Western world. Screening with fecal occult blood tests is based on the concept that important target colonic neoplasm, such as early-stage cancer and large adenomatous polyps, will bleed, for which may be detected by an occult blood test. When gastrointestinal blood is lost, the stool will contain a combination of intact or nearly intact hemoglobin, intact heme, and heme-derived porphyrins in amounts that depend on the site, the amount of bleeding and the transit time through the gut. Immunochemical tests detect intact or nearly intact human hemoglobin, being a very specific technique to detect the loss of blood from the lower intestine, because blood from lower sites is less degraded during transit. The hemoglobin is unstable in feces, leading to false negative results.

The detection of fecal transferrin, which is more stable than hemoglobin, provides an alternative way of diagnosing the disease in the upper digestive tract. Transferrin is a blood-derived component that may be leaked into gastrointestinal tract and then discharged with the feces in gastrointestinal bleeding diseases. Transferrin is stable in feces and a good marker to detect loss of blood from the upper and lower intestine (gastrointestinal bleeding). This immunochromatographic assay detects human hemoglobin and human transferrin in stool samples simultaneously, by obtaining more accurate testing results.