ISSN 2398-2969      

Staining technique: Giemsa



  • A type of Romanowsky stain widely used for evaluating blood smears, bone marrow aspirates and fine needle aspirate biopsy specimens, especially from lymph nodes. 
  • A differential stain, Giemsa can help identify blood parasites such as malaria, and may also be used to identify Chlamydia and mast cells. 
  • The choice of stain used is dependent on availability of equipment and staining solutions in practice, the experience and preference of the clinician.
  • Stains can be either applied manually with the aid of cuvets, or mechanically in automated staining systems.  
  • Romanowsky stains are neutral stains composed of a mixture of oxidized methylene blue (azure) dyes and Eosin Y. 
  • 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.
  • Structural details are very apparent with Giemsas stain.
  • Buffer is critical to force the dyes to precipitate out of solution to bind sample material.
  • Giemsas solution can be combined with May-Grunwalds solution   Staining technique: May-Grunwald   solution to produce the Pappenheims stain enabling excellent results to be obtained for clinical samples. This can be used for urinary sediments, effusions, bronchial lavage material and fine needle aspirate material.


  • Stain cells to identify abnormalities in morphology and pathological changes.
  • To identify bacterial adhesion and chromosome abnormalities.
  • Positive stain to identify Dermatophilus congolensis (more accurate method than gram stain).


  • Easy to prepare.
  • Readily available.
  • Provides excellent cytoplasmic and nuclear detail.
  • Stains bacterial organisms.


  • Giemsa stain must be prepared shortly before use.
  • Giemsa must be stored in the dark.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Cray C & Zaias J (2004) Laboratory procedures. Vet Clin Exotic Anim Pract (2), 487-518 PubMed.

Other sources of information

  • Merck KGaA (2013) Cytodiagnosis Staining Methods. In:Merck Millipore Manual.
  • Dunn J K & Gerber K (2005) Diagnostic Cytology. In:BSAVA Clinical and Feline Clinical Pathology. 2nd edn.  Eds: Villiers E & Blackwood L. BSAVA, Gloucester. pp 305-339. 
  • Dacia Sir J V & Lewis S M (2001) Practical Haematology. 6th edn. Longman Singapore Publishers Pte Ltd. pp 50-61.


  • Mary Pinborough, Pinmoore Animal Laboratory Services Ltd, The Coach House, Town House Barn, Clotton, Cheshire CW6 0EG, UK. Tel: +44 (0)1829 781855; Email: ; Website: .

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