What is Phenolphthalein (Kastle – Mayer Test) ?
This test is also known as Kastle-Mayer Test.
The kastle- mayer solution is of phenolphthalein indicator solution which have been produce usually by reacting with Zn powder and ZnO.
It’s Uses In Forensics
This Test Is an Inexpensive, Easy and Realiable For Examination of Blood.
It’s Sensitivity Is 1:107 In Dilution.
It is more Sensitive than Benzidine Test.
Basis Of The Test
The basis of the test is that the peroxidase-like activity of hemoglobin in blood catalysis.
Indication for the Presence of Blood
It Produce Pink Color which Indicate Presence Of Blood.
How To Perform This Test ?

If the test is negative, it is reasonable proof that “heme” is absent.
Drawbacks
It Also Give Positive Result In The Case Of Plant Or High Oxygenated Compound.
It Also Give Positive Result for heme molecule of different species so It is hard to differentiate if blood is of human or other species.