What is Giemsa Stain?

Giemsa stain is a gold standard staining technique that is used for both thin and thick smears to examine blood for malaria parasites, a routine check-up for other blood parasites, and to morphologically differentiate the nuclear and cytoplasm of Erythrocytes, leucocytes, and Platelets, and parasites.

Like any type of Romanowsky stains, it is composed of both Acidic and Basic dyes, in relation to affinities of acidity and basicity for blood cells. Azure and methylene blue, a basic dye binds to the acid nucleus producing blue-purple color. Eosin is an acidic dye that is attracted to the cytoplasm and cytoplasmic granules which are alkaline-producing red coloration. The stain must be buffered with water to pH 6.8 or 7.2, to precipitate the dyes to bind simple materials.

Classically, Giemsa stain is a differential stain that is made up of a combination of reagents (Azure, Methylene blue, and Eosin dye) used widely in cytogenetics and histopathology for the diagnosis of:

1. Malaria, spirochetes, and other blood parasites
2. Chlamydia trachomatis inclusion bodies
3. Borrelia spp
4. Yersinia pestis
5. Histoplasma spp
6. Pneumocystis jiroveci cysts