Wright stain

histological stain for the differentiation of types of blood cells.

Description
The Wright stain (or Wright's stain) is mainly used to stain peripheral blood smears and bone marrow aspirates for examination by light microscopy. Additionally, it is used in cytogenetics to stain chromosomes in the diagnosis of syndromes and diseases.

Wright's stain is the combination of a basic blue dye (methylene blue)and a red acidic dye (eosin) and differentially stains various types of leukocytes, such eosinophils or basophils, to allow their precise enumeration. The stain was developed by James Homer Wright in 1902 as a modification of the Romanowsky stain, and owing to its speedy application and its utility in differential blood cell counts, it fast became popular in hematology. There are other staining procedures in use, such as the May-Grünwald Giemsa, which takes longer to perform but stains more intensely.