Tissue processing and hematoxylin and eosin staining.

The hematoxylin and eosin (H&E) stained tissue section is the cornerstone of anatomical pathology diagnosis. The H&E procedure stains the nucleus and cytoplasm contrasting colors to readily differentiate cellular components. However, staining results are dependent on proper specimen processing, which involves tissue preservation, dehydration, clearing, and paraffin infiltration. While improvements in instrumentation for both tissue processing and staining have been beneficial, limitations in the chemical reagents used must always be considered.