HEstained

HEstained refers to tissue or cells that have been stained using the hematoxylin and eosin staining technique. This combined stain, commonly abbreviated H&E, is the standard method in light microscopy for histology and pathology to reveal tissue architecture and cellular details.

Hematoxylin is a basic dye that binds to acidic structures, staining nuclei blue or purple, while eosin is an acidic dye that stains basic structures such as cytoplasm, collagen, and extracellular matrix pink to red. The contrasting colors create clear differentiation between nuclear and cytoplasmic components, aiding morphological assessment.

The typical workflow involves fixing the tissue, processing and embedding in paraffin, sectioning into thin slices, and performing staining. The section is first stained with hematoxylin, often followed by a bluing step to enhance nuclear color, then counterstained with eosin, dehydrated, cleared, and mounted for microscopy. The result is a stable slide suitable for examination.

In diagnostic practice, HEstained sections are used to evaluate tissue organization, cell shape, nuclear features, and the presence of abnormalities such as inflammation, necrosis, fibrosis, or tumors. They are widely used in pathology laboratories for biopsy and resection specimens and also serve as a common reference in educational settings and research.

Limitations include that H&E does not identify specific molecules or cell types without supplementary stains or immunohistochemistry. Staining quality can vary with fixation, processing, and dye lots, and some tissue components may be difficult to distinguish. Artifacts and fading can affect interpretation.