H&E stain

Hematoxylin and eosin stain or haematoxylin and eosin stain (often abbreviated as: H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnosis and is often the gold standard; for example, when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E. Cartilage, cell nuclei (blue-purple), extracellular material (pink).Ductal carcinoma in situ (DCIS) in breast tissue, cell nuclei (blue-purple), extracellular material (pink).Lung tissue taken emphysema patient. Cell nuclei (blue-purple), red blood cells (bright red), other cell bodies and extracellular material (pink), and air spaces (white).Muscle tissue, cell nuclei (blue-purple), extracellular material (pink).Basal cell carcinoma of the skin, cell nuclei (blue-purple), extracellular material (pink). Hematoxylin and eosin stain or haematoxylin and eosin stain (often abbreviated as: H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnosis and is often the gold standard; for example, when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E. H&E is the combination of two histological stains: hematoxylin and eosin. The hematoxylin stains cell nuclei blue, and eosin stains the extracellular matrix and cytoplasm pink, with other structures taking on different shades, hues, and combinations of these colors. The stain shows the general layout and distribution of cells and provides a general overview of a tissue sample's structure.Hence a pathologist can easily differentiate between the nuclear and cytoplasmic parts of a cell. This stain combination was first introduced in 1876 by A. Wissowzsky. The H&E staining procedure is the principal stain in histology in part because it can be done quickly, is not expensive, and stains tissues in such a way that a considerable amount of microscopic anatomy is revealed, and can be used to diagnose a wide-range of histopathologic conditions. The results from H&E staining are not overly dependent on the chemical used to fix the tissue or slight inconsistencies in laboratory protocol, and these factors contribute to its routine use in histology. H&E staining does not always provide enough contrast to differentiate all tissues, cellular structures, or the distribution of chemical substances, and in these cases more specific stains and methods are used. There are many ways to prepare the hematoxylin solutions (formulation) used in the H&E procedure, in addition, there are many laboratory protocols for producing H&E stained slides, some of which may be specific to a certain laboratory. Although there is no standard procedure, the results by convention are reasonably consistent in that cell nuclei are stained blue and the cytoplasm and extracellular matrix are stained pink. Histology laboratories may also adjust the amount or type of staining for a particular pathologist. After tissues have been collected (often as biopsies) and fixed, they are typically dehydrated and embedded in melted paraffin wax, the resulting block is mounted on a microtome and cut into thin slices. The slices are affixed to microscope slides at which point the wax is removed with a solvent and the tissue slices attached to the slides are rehydrated and are ready for staining. Alternatively, H&E stain is the most used stain in Mohs surgery in which tissues are typically frozen, cut on a cryostat (a microtome that cuts frozen tissue), fixed in alcohol, and then stained. The H&E staining method involves application of hematoxylin mixed with a metallic salt, or mordant, often followed by a rinse in a weak acid solution to remove excess staining (differentiation), followed by bluing in mildly alkaline water. After the application of hematoxylin, the tissue is counterstained with eosin (most commonly eosin Y). Hematoxylin principally colors the nuclei of cells blue or dark-purple, along with a few other tissues, such as keratohyalin granules and calcified material. Eosin stains the cytoplasm and some other structures including extracellular matrix such as collagen in up to five shades of pink. The eosinophilic (substances that are stained by eosin) structures are generally composed of intracellular or extracellular proteins. The Lewy bodies and Mallory bodies are examples of eosinophilic structures. Most of the cytoplasm is eosinophilic and is rendered pink. Red blood cells are stained intensely red.