The standard Romanowsky-Giemsa stain in histology

A new and technically simple Romanowsky-Giemsa (RG) stain is proposed as a standardized technique for use in histology. An RG stock solution (pure azure B 7.5 g/l, eosin Y as eosinic acid 1.2 g/l in dimethylsulfoxide) is diluted to form the working solution with HEPES-buffer, pH 6. Staining time is 30-90 min after formol-calcium solution (or 2-4 hr after formaldehyde-organic acid mixtures). The resulting overstained sections are to be differentiated. A tannic acid-acetic acid combination in an isopropanol-water mixture was found to give optimum results within 100 sec. Subsequent dehydration is in isopropanol only. The staining pattern obtained is polychrome. The distribution of colors in detail is influenced by the modes of pre- and posttreatment. Of practical interest is the development of green and greenish blue colors on collagen fibrils which contrast strongly against the pink of sarcoplasm. For this and other reasons, this RG stain version seems suitable to replace the trichrome Gomori-type trichrome stains under appropriate processing conditions.