May Grunwald Giemsa (MGG) Staining
Introduction
May Grunwald Giemsa stain is one of many stains under the Romanowsky staining procedure. It is a combination of two stains, May Grunwald stain and Giemsa stain. Like other Romanowsky stains, the principle is the same. It is used for bone marrow smear staining.
Materials
- May Grunwald dye
- Absolute methanol
- Giemsa dye
- Glycerol
- Phosphate buffer pH 6.8
Method
Preparation of May Grunwald stain
- Dissolve 0.3 g of May Grunwald dye in 100 mL absolute methanol in a 250 mL conical flask.
- Warm the mixture to 50°C in a water bath for a few hours and allow it to cool to room temperature.
- Stir the mixture on a magnetic stirrer and leave it stirring for 24 hours.
- Filter the mixture and stain is ready for use.
Preparation of Giemsa stain
- Add 1.0 g of Giemsa dye into 66 mL of glycerol and warm the mixture in a conical flask for 1-2 hours at 50°C.
- Cool the mixture to room temperature and add 66 mL of absolute methanol.
- Leave the mixture to dissolve for 2-3 days, mixing it at intervals.
- The stain is then ready for use after filtering.
Staining
- Fix BM smears in absolute methanol for 10-15 minutes.
- Prepare an equal volume of May Grunwald stain and phosphate buffer pH 6.8. Mix well and pour onto the slides to fully flood the slides. Stain for 10 minutes.
- Prepare a 1:10 dilution of Giemsa stain with phosphate buffer pH 6.8. Mix well.
- After 10 minutes of May Grunwald staining, pour away the May Grunwald stain off the slides.
- Then pour the Giemsa mixture onto the slides and stain for another 15 minutes.
- After 15 minutes, pour off stain and flush the slides with running tap water.
- Clean excess stain with kim wipes.
- Air dry the slides. *Hair dryer can be used to dry the slides but must be used at the lowest speed and no longer than 10 seconds each time.
- Place the long cover slip on the area of interest.
- The slide is now ready for examination.

Bone marrow smear x400 magnification.