Fair to poor.
Pale gray, peach or yellow solution.
Classic test for the presence of blood at a crime scene! Kastle–Meyer reagent contains reduced phenolphthalein indicator in a basic solution. Simply wipe a presumptive bloodstain with a cotton swab, add a drop of the reagent, and then apply a drop of hydrogen peroxide. If the swab turns pink rapidly, it is positive for blood! For a terrific guided-inquiry forensic activity, use the Kastle–Meyer reagent to investigate substances that will interfere with the test to give false positives.