Final answer:
The most common color test for blood is the Wright-Giemsa stain. This stain is used to identify bloodstains by staining red blood cells a pinkish-red color, and staining the nucleus and cytoplasm of white blood cells various shades of purple.
Step-by-step explanation:
The most common color test for blood is the Wright-Giemsa stain. This stain is used to identify bloodstains by staining red blood cells a pinkish-red color, and staining the nucleus and cytoplasm of white blood cells various shades of purple. Stained blood smears are then examined under a microscope to evaluate the appearance of the blood cells and to count the number of different types of white blood cells present.