Wright Stain

Wright’s stain is a histologic stain that facilitates the differentiation of blood cell types. It is classically a mixture of eosin (red) and methylene blue dyes. It is used primarily to stain peripheral blood smears, urine samples, and bone marrow aspirates which are examined under a light microscope.

Reagents

The dye may be purchased as a powder which is then mixed to methanol or a ready-made solution may be obtained.

1. Staining Solution
   Wright’s stain powder = 1.0 gm
   Water free methanol = 400 ml
2. Phosphate buffer (0.15M, ph 6.5/6.8)
   Potassium dihydrogen phosphate, anhydrous = 0.663 gm
   Disodium hydrogen phosphate, anhydrous = 0.256 gm
   Distilled water = 100 ml

Storage and Shelf life:

Wright’s Stain should be stored at room temperature and protected from light. Under these conditions it has a shelf life of 52 weeks from the date of manufacture.

Procedure:

• Dip slide for a few seconds in methanol as a fixative step and allow slide to air dry completely.
• Place slide on a level staining rack and place 1.0 ml of the Wright Stain Solution upon the smear 1 – 3 minutes.
• Add 2.0 ml distilled water or Phosphate buffer pH 6.5 and let stand twice as long as 1-3 minuts.
• Rinse stained smear with water or the Phosphate buffer pH 6.5 until the edges show faintly pinkish-red.
• Wipe the underside of the slide and let the slide air dry in a vertical position.
• Examine the slide under the microscope.

Results:

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