Lapis ISSN 2398-2969

Staining technique: Romanowsky stains - overview

Synonym(s): Romanowsky

Contributor(s): Molly Varga, Sarah Pellett


  • The choice of stain used is dependent on availability of equipment and staining solution in practice, the experience and preference of the clinician.
  • Stains can be either applied manually with the aid of cuvettes, or mechanically in automated staining systems.
  • Romanowsky stains are neutral stains composed of a mixture of oxidized methylene blue (azure) dyes and eosin Y.
  • Romanowsky staining is the prototypical cytological staining method. Changes in the methodology have lead to the evolution of other linked staining methods.
  • Romanowsky stains include Wright's, Giemsa, Wright-Giemsa, May-Grunwald-Giemsa and Diff-Quik.
  • Buffer is essential to enable the dyes to precipitate out of the solution and bind to sample material.
  • The azures are basic dyes that bind acid nuclei and result in a blue to purple color.
  • The eosines are acidic dyes that are attracted to the alkaline cytoplasm, producing red coloration.
  • They generally provide excellent nuclear detail and also clear differentiation of the cytoplasm.
  • The alcohol based 'fast' staining kits such as Diff-Quik are readily available and commonly used in practice.

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