The heme group of blood (hemoglobin in particular) in the presence of hydrogen peroxide oxidizes alpha-guaiaconic acid (a component of guaiac resin, a substance produced from the Guaiacum tree species) to blue-green colored qui- none within 30-180 seconds.
The card test contains a special filter paper impregnated with natural guaiac resin and a color reagent containing hy- drogen peroxide.
The blue-green color produced after the addition of hydro- gen peroxide helps in the detection of occult (hidden) blood.
Turklab’s Gikan card test is a card test for the qualitative de- tection of occult (hidden) blood in stool as an aid in the de- tection and diagnosis of gastrointestinal diseases.
• Sensitivity: 96.0%
• Specificity: 95.0%