The stool guaiac test or guaiac fecal occult blood test (gFOBT) is one of several methods that detects the presence of fecal occult blood[1] (blood invisible in the feces).[2] The test involves placing a fecal sample on guaiac paper (containing a phenolic compound, alpha-guaiaconic acid, extracted from the wood resin of Guaiacum trees) and applying hydrogen peroxide which, in the presence of blood, yields a blue reaction product within seconds.
The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of the fecal immunochemical test (FIT).[3] Though the FIT is preferred, even the guaiac FOB testing of average risk populations may have been sufficient to reduce the mortality associated with colon cancer by about 25%.[4] With this lower efficacy, it was not always cost effective to screen a large population with gFOBT.[5][6][7][8]
^Bretthauer M (August 2010). "Evidence for colorectal cancer screening". Best Pract Res Clin Anaesthesiol. 24 (4): 417–25. doi:10.1016/j.bpg.2010.06.005. PMID20833346.
^Kewenter J, Brevinge H, Engaras B, et al. (1994). "Results of screening, rescreening and follow up in a prospective randomized study for detection of colorectal cancer by fecal occult-blood testing: results of 68,308 subjects". Scand J Gastroenterol. 29 (5): 468–73. doi:10.3109/00365529409096840. PMID8036464.