Brilliant cresyl blue is a

supravital stain Supravital staining is a method of staining used in microscopy to examine living cells that have been removed from an organism. It differs from intravital staining, which is done by injecting or otherwise introducing the stain into the body. Thu ...

used for counting

reticulocyte Reticulocytes are immature red blood cells (RBCs). In the process of erythropoiesis (red blood cell formation), reticulocytes develop and mature in the bone marrow and then circulatory system, circulate for about a day in the blood stream before ...

s. It is classified as an

oxazine dye Oxazines are heterocyclic compounds containing one oxygen and one nitrogen atom in a doubly unsaturated six-membered ring. Isomers exist depending on the relative position of the heteroatoms and relative position of the double bonds. By extensi ...

. N95 dust masks, eye shields, and gloves must all be worn when handling the chemical.

References

{{heterocyclic-stub Chlorides Zinc compounds Oxazine dyes Phenoxazines