WRIGHT'S ONE-STEP STAINING

INTRODUCTION

The traditional Wright's stain dates from the early 1890's. The original Wright's stain was an alcoholic solution of methylene blue and eosin Y. Since then, there have been many modifications, most involving partial oxidative demethylation of the methylene blue to improve polychroming. Modern day samples of the dye usually contain mixtures of methylene blue, azure A, thionin and eosin Y. They also contain some amount of giemsa stain.

The traditional stain is diluted 1:1 with giordano buffer before use. Wright's One Step stain contains the buffer already dissolved in the stain. The slides are stained in the undiluted stain and differentiated by decolorizing in purified water.

REAGENTS

PRODUCT #	DESCRIPTION	PACKAGING
929A-16oz	Wright's One Step	16 oz.
929A-32oz	Wright's One Step	32 oz.
929A-1gl	Wright's One Step	1 gallon

Note: Med Chem also manufactures a traditional Wright's stain (Cat#926A) and a Dip Stat procedure (Cat#300).

SPECIMEN COLLECTION

Freshly drawn blood that does not contain an anticoagulant is preferred. Fresh, EDTA treated blood may also be used but the anticoagulant will distort the cells. The sample should not be exposed to excessive heat. Hemolysis will render the sample unsatisfactory. Smears should be made in the usual way and air dried. Thin smears work best.

PROCEDURE

Dip Method:

1. Dip air dried smears in undiluted stain for 15 to 30 seconds.

2. Decolorize the stained smears by immersion in deionized or distilled water for 15 to 45 seconds.

Rack Method:

1. Lay fixed slides on staining rack and flood with stain. Stain for 10 to 15 seconds.

2. Add an equal volume of deionized/distilled water and stain for 10 seconds.

3. Rinse the slide by dipping in deionized/distilled water for 30 seconds. The slide may also be rinsed by swishing or washing with deionized/distilled water.

Rinse, air dry and examine stained smears under oil immersion in the usual manner. Staining times are approximate and should be varied as needed. Double the times for bone marrow smears.

SOURCES OF ERROR

1. Smears should not be too thick.

2. All glassware should be scrupulously clean.

3. Smears should be fixed and stained as soon as possible, preferably within one hour of collection.

4. The rinsing solution should be deionized or distilled water. Tap water is not suitable because the chlorine will bleach the stain.