Answer:
Determines if the stain is indeed blood.
Step-by-step explanation:
The Kastle-Meyer blood test is primarily used to determine if a stain is indeed blood. It is a presumptive test, meaning it provides an initial indication of the presence of blood but does not definitively confirm it. The test relies on the chemical reaction between hemoglobin (a protein found in red blood cells) and a reagent called phenolphthalein. When blood is present, the reaction causes a change in color, typically from colorless to pink or reddish. This color change indicates a positive result for the presence of blood.