Methodology

In this test, alpha guaiaconic acid (active component of the developer) in the presence of heme (peroxidative-type of catalyst present in hemoglobin) to produce a highly conjugated blue quinine compound.

The Gastoccult slide includes both a specially buffered guaiac test for occult blood and a pH test based on the principle that certain dyes change color with changes in hydrogen ion concentration. This test is designed to be used with gastric samples since the occult blood test is not affected by low pH.