SYSMEX SP-50 - Staining Principles

Analyser components – Staining Principles
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Staining Principles
Romanowsky stains, such as Giemsa, Leishman and May-Grunwald, are used widely for the routine
staining of peripheral blood films. Whichever combination of stains is used the distinction in staining is
achieved due to the balance of basic and acidic components within the stains.
The colour and particular cellular component stains, is dependent on the binding that occurs between
the staining compounds and chemical structures within the cell, as well as interaction between dye
molecules, pH and time.
Whichever combination of stains are used the process must be carried out at the correct pH. If the pH
is too acidic the basophilic components appear too pink. If the pH is too alkaline conversely there is over
staining as too much basic stain is taken up.
These reaction are also dependent on time as DNA binds to staining compounds more rapidly than RNA
and Haemoglobin is even slower. As a results incorrect concentration of stains and/or timings will result
in poor stains.
Cellular Component
Staining Principle
Proteins and Nucleic Acids
Both bind to the basic component of the stain. This results in a blue-
violet
or blue colour.
Haemoglobin
Has a high affinity for the more acidic components of the stain
resulting in a
red
or orange colour.
Eosinophil Granules
Eosinophil granules have a basic components which have a strong
affinity for acidic components of the stain resulting in a
red
or orange
colour.
Basophil Granules
Basophil granules contain heparin which are strongly acidic and
therefore have a strong affinity for the basic component resulting in
dark purple
colour.