Colloidal Immunization Method: One-Step Fecal Occult Blood (FOB) Diagnostic Kit is a immunoassay for the determination of human hemoglobin (Hb) in feces. Antibodies to Hb are precoated onto membrane as a capture reagent on the test zone. During the test, specimen is allowed to react with the colloidal gold particles, which have been labeled with antibodies to Hb. If Hb is present, a red colored line will develop on the membrane in proportion to the amount of Hb present in the specimen. To serve as a procedural control, red colored line in the control zone will always appear regardless of the presence of Hb.
Chemical Method: Hemoglobin has peroxidase activity which can cause peroxide decompose then release oxygen atom. The oxygen atom oxidizes 3, 3’, 5, 5’-tetramethyl-benzidine indicator, which have been combined with the kit to change the color. When specimen contains a certain amount of Hb, the color will change from orange to yellow-green or dark green. Very high concentration of Hb, may cause the color development to dark blue.
