<prompt> Guaiac test is used forPentosuriaFructosuriaFor occult blood in stoolPancreatitis  <response>: Based on the property of an organic compound, guaiac, to turn blue after oxidation by oxidants, peroxidases, or the pseudoperoxidase of hemoglobin in the presence of an oxygen donor such as hydrogen peroxide. Guaiac tests are more sensitive for detecting bleeding from the lower than from the upper GI tract because hemoglobin and its pseudoperoxidase activity is degraded as it moves down the GI tract. Fecal hemoglobin levels must exceed 10 mgg blood loss of 10 ml daily for 50 of Hemoccult II tests to be positive. 