Field Stain

Field stain is a histological method for staining of blood smears. It is used for staining thick blood films in order to discover malarial parasites. Field’s stain is a version of a Romanowsky stain, used for rapid processing of the specimens.

Principle:

• Field’s stains contain methylene blue and eosin.
• These basic and acidic dyes induce several colours when applied to cells.
• The fixator, methanol, does not allow any additional changes to the slide.
• The basic component of peripheral white blood cell( cytoplasm) is stained with acid dye and described as eosinophil or acidophil.
• The acid component that is nucleic acid of the nucleus takes on the basic dye and is stain blue to violet  called basophil.
• The neutral components of the cells are stained by both dyes(Field’s stain A and B solution)

Somposition:

Field’s Stain A

Field’s Stain B

• Field’s stain A has is a dark violet coloured solution
• Field’s stain B has is an orange coloured solution

Procedure:

1. Place a drop of blood on a slide and spread it over an area of about 1 cm2.( The film should be distributed so thinly that it appears transparent.
2. Allow the film to air dry (Do not fix the slide)
3. Flood or dip the slide in Field’s Stain A for 2-3 seconds.
4. Wash or rinse the slide with distilled water (Agitate gently)
5. Flood or dip the slide in Field’s Stain B for 2-3 seconds and wash with distilled water.
6. Now air dry  the smear or slide and observe under microscope.

Results:

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