Hematoxylin is a basic dye that gives a blue or blue-black color to acidic substances in cells and tissues. Thus the chromatin of the nuclei composed of desohyribonucleic acid is colored in dark blue by hematoxylin. In the same way, the cytoplasm is colored more or less intensely in blue due to the ribosomes which contain the ribonucleic acid. Substances or structures that stain blue with hematoxylin are called basophilic.
Hematoxylin is very commonly used in histology laboratories for routine staining. It is often associated with eosin to obtain a complete labeling of cellular structures.
There are now several hematoxylins called "modified":
- Hematoxylin H : Modified hematoxylin according to Harris, most commonly used formulation in HE staining.
- Hematoxylin M : Modified hematoxylin according to Mayer. Weaker intensitiy reagent.
- Hematoxylin ML : Modified hematoxylin according to Mayer-Lillie. Strong intensity new generation reagent.
- Hematoxylin G1 : Hematoxyline according to Gill, ideal for staining globet cells.
- Hematoxylin G2 : Hematoxylin according to Gill, contains double concentration of hematoxylin compared to Hematoxylin G1
- Hematoxylin G3 : Hematoxylin according to Gill, contains triple concentration of hematoxylin compared to Hematoxylin G1
- Hematoxylin W : Acid resistant hematoxylin according to Weigert
- Hematoxylin PTA : Hematoxylin Phosphotungstic Acid Mallory PTHA reagent. For differentiation between fibrin, smooth and cross-striated muscle fibers
- Hematoxylin CAR : Modified hematoxylin according to Carazzi for delicate nuclear staining without staining cytoplasmic components
- Hematoxylin COL : Modified hematoxylin according to Cole, contains iodine