Wright's stain is a hematologic stain that facilitates the differentiation of blood cell types. 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.
Proper buffer selection is very important in achieving good quality staining. If a buffer is too acidic the stain will be too red and nuclei will be too light; if it is too basic the stain will be too blue and cytoplasmic detail will be indistinct.
Wright's stain is a polychromatic stain consisting of a mixture of Eosin and Methylene blue. As the Wright stain is methanol based, it doesn't require a fixation step prior to staining. However, fixation helps to reduce water artefact that can occur on humid days or with aged stain.
The main difference between Giemsa stain and Wright stain is that Giemsa stain is used to stain chromosomes to identify chromosome aberrations. But, Wright stain is used to differentiate blood cell types.
