Haematology Stains: The Pathologist’s Dilemma

The stain used to prepare blood smears for microscopic examination varies greatly throughout laboratories, but the majority of stains used today are derived from Romanowsky stains. The origin of Romanowsky stain can be found in the early 1900s, when Russian physician Dmitri Romanowsky created a staining method using methylene blue and eosin, that has transformed histology procedures by significantly enhancing the visibility and contrast of cellular characteristics.

In summary, Romanowsky stain is mostly utilized in the differential staining of blood smears. Examples of stain types include Giemsa, Wright, Jenner, May-Grünwald, Leishmann, and fields stain. In practice, a pathologist's preference is frequently more important when selecting stains for hematological specimens than making a technically incorrect decision. It's crucial to understand when to use these stains and when it could be preferable to use a different solution.

Wright and Giemsa stains are the cost-effective and adaptable solution for today's labs. Excellent for regular blood smears as well as the staining of bone marrow, platelets, and blood parasites. These stains were created to provide higher cellular detail and quicker staining. Wright stain is frequently used in differential white blood cell counts, whereas Giemsa stain is mostly used in the demonstration of malarial parasites in blood smears.

Wright stain produces more eosinophilic or less intense stain, while its variant Wright-Giemsa stain is developed to create more intense basophilic/nuclear staining in blood cell morphology. One variation of the Romanowsky stain that is used to prepare specimens quickly is the field stain. It is especially helpful in situations with limited resources when cutting-edge laboratory equipment is unavailable.

Romanowsky staining has been used extensively in laboratories across the globe since its invention and has shown to be a valuable tool in the study of cellular morphology and disease. These stains have been developed in a multitude of forms and variations that meet distinct diagnostic requirements and deepen our knowledge of a wide range of biological specimens.

However, there are certain challenges with the staining too, like its variability and the requirement for strict quality control. But the merger of automation and artificial intelligence promises to improve accuracy and productivity. Today, as we stand at the crossroads of manual and digital modes, these stains continue to be a keystone in histology, guiding researchers and clinicians in unlocking the complexities of cellular structures.

Let's examine the fundamental distinctions between the most often used stains in laboratories.

 

References

1.  Horobin RW. How Romanowsky stains work and why they remain valuable - including a proposed universal Romanowsky staining mechanism and a rational troubleshooting scheme. Biotech Histochem. 2011 Feb;86(1):36-51.

2.  Kalinin V, Padnya P, Stoikov I. Romanowsky staining: history, recent advances and future prospects from a chemistry perspective. Biotech Histochem. 2024 Nov;99(1):1-20.

3.     koka Mbassi FA, Mombo-Ngoma G, Ndoumba WN, Yovo EK, Eberhardt KA, Ekoka Mbassi D, Adegnika AA, Agnandji ST, Bouyou-Akotet MK, Ramharter M, Zoleko-Manego R. Performance of Field's Stain Compared with Conventional Giemsa Stain for the Rapid Detection of Blood Microfilariae in Gabon. Am J Trop Med Hyg. 2022 Jul 5;107(2):383-387.