Histology / Histopathology

Despite the growing usage of antibody immunolabeling techniques in research and medicine today, clinical diagnostics remains largely centered on analysis based on well-established stains and dyes classified as routine, differentiating, and special. Routine stains like H&E are used as ubiquitous background stains. Differentiating stains include combinations of stains and counterstains to reveal more anatomical detail. Special stains are used in more detailed analyses, where closely related cell types need to be differentiated. Although some standard protocols are over 100 years old, histological staining is a vibrant and evolving field.

Staining in Histopathology

Numerous staining techniques were initially developed in an empirical way for analyzing tissue sections. The most specific staining mixtures were then developed for the staining and recognition of cell nuclei, cytoplasm, intra- and extra-cellular components.

Classical techniques, like H&E and Fuchsin staining, are adequate for most diagnoses (90-95%) however, some diagnosis require additional differential staining methods. These special methods (e.g., Wright-Giemsa, Schiff staining) enable the evaluation of additional morphological criteria and functional properties, ultimately making the final diagnosis more reliable. Additional techniques are now used to augment histopathologic analysis including immunohistochemical methods, DNA hybridization, fluorescence in situ hybridization, PCR, and flow cytometry.