A modified reagent for the confirmation of blood

Oxygen and pyridine compete for the same binding site on the heme molecule. Lowering the oxygen concentration in Takayama's reagent by addition of an oxygen scavenger such as dithiothreitol (Cleland's reagent) shifts this equilibrium in favor of pyridine, and increases the rate at which hemochromogen crystals are formed. This modification makes the confirmatory test for blood faster, and therefore easier to use. The absolute sensitivity and the specificity of the reagent appear unchanged.