<Li> Stool guaiac test for fecal occult blood (gFOBT):--The stool guaiac test involves smearing some feces onto some absorbent paper that has been treated with a chemical . Hydrogen peroxide is then dropped onto the paper; if trace amounts of blood are present, the paper will change color in one or two seconds . This method works as the heme component in hemoglobin has a peroxidase - like effect, rapidly breaking down hydrogen peroxide . In some settings such as gastric or proximal upper intestinal bleeding the guaiac method may be more sensitive than tests detecting globin because globin is broken down in the upper intestine to a greater extent than is heme . There are various commercially available gFOBT tests which have been categorized as being of low or high sensitivity, and only high sensitivity tests remain an acceptable alternative to FIT testing, which is now the best - practices recommendation in colon cancer screening . Optimal clinical performance of the stool guaiac test depends on preparatory dietary adjustment . </Li> <Li> Stool DNA screening tests look for DNA alterations that have been associated with cancer . </Li> <P> Additional methods of looking for occult blood are being explored, including transferrin dipstick and stool cytology . </P> <P> The estimates for test performance characteristics are based on comparison with a variety of reference methods including 51 - chromium studies, analytical recovery studies in spiked stool samples, analytical recovery after ingestion of autologous blood, rarer studies of carefully quantified blood instilled at bowel surgery as well as other research approaches . Additionally, clinical studies look at variety of additional factors . </P>

The fobt is an abbreviation for the test to detect