Wright's stain

It is classically a mixture of eosin (red) and methylene blue dyes.

It is used primarily to stain peripheral blood smears, urine samples, and bone marrow aspirates, which are examined under a light microscope.

In cytogenetics, it is used to stain chromosomes to facilitate diagnosis of syndromes and diseases.

Because it distinguishes easily between blood cells, it became widely used for performing differential white blood cell counts, which are routinely ordered when conditions such as infection or leukemia are suspected.

[1] The May–Grünwald stain, which produces a more intense coloration, also takes a longer time to perform.

Wright's stain, with red blood cells taking up eosin Y, azure B giving nuclei a purple color, and methylene blue coloring the cytoplasm of this plasmablast .