May Grunwald Giemsa (MGG) Staining


Similar to the Leishman stain, MGG is part of the Romanowsky stains and adopts the same principle. MGG stain consists of May Grunwald stain and Giemsa stain. MGG stain is used for morphology assessment of bone marrow aspirates especially in diseases like chronic lymphocytic leukemia, chronic myeloid leukemia, aplastic anemia. 

Principle of MGG stain

MGG stain works by differentially staining different cellular components based on their acidic or basic properties. Acidic components, such as DNA and chromatin, stain blue or purple, while basic components, such as cytoplasm and proteins, stain pink or red. The stain also highlights nuclear structures, such as nucleoli and nuclear membranes.

MGG stain is used to visualize cells in a variety of tissues, including blood, bone marrow, and lymph nodes. It is particularly useful for identifying and classifying different types of white blood cells, such as lymphocytes, granulocytes, and monocytes. It can also be used to detect abnormalities in cells, such as the presence of cancer cells or infection.

Method differs slightly according to the manufacturer’s protocol.


  • May Grunwald dye
  • Absolute methanol
  • Giemsa dye
  • Glycerol
  • Phosphate buffer pH 6.8


Preparation of May Grunwald stain

  1. Dissolve 0.3 g of May Grunwald dye in 100 mL absolute methanol in a 250 mL conical flask.
  2. Warm the mixture to 50°C in a water bath for a few hours and allow it to cool to room temperature.
  3. Stir the mixture on a magnetic stirrer and leave it stirring for 24 hours.
  4. Filter the mixture and stain is ready for use.

Preparation of Giemsa stain

  1. 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.
  2. Cool the mixture to room temperature and add 66 mL of absolute methanol.
  3. Leave the mixture to dissolve for 2-3 days, mixing it at intervals.
  4. The stain is then ready for use after filtering.


  1. Prepare a solution of May Grunwald stain and phosphate buffer at 1:1 ratio and mix well.
  2. Prepare a 1:10 dilution of Giemsa stain with phosphate buffer pH 6.8 and mix well.
  3. Fix bone marrow aspirate smear in absolute methanol for 10 -15 minutes.
  4. Fully cover the slide with May Grunwald-phosphate mixture and incubate for 10 minutes.
  5. Decant the May Grunwald-phosphate mixture from the slide and fully cover the slide with the Giemsa-phosphate mixture.
  6. Incubate for 15 minutes.
  7. Decant the mixture and rinse the slide with slow running tap water.
  8. Wipe the back of the slide and edges with Kim wipes. Be careful not to touch the smear. 
  9. Dry the slide using a hair dryer on the lowest speed (not more than 10 seconds at a time) or air dry in a tilted position.
  10. Mount the slide with Depex and cover the zone of morphology with a long cover slip. 
  11. This slide is now ready for viewing.
Visualizing the Cellular Landscape of Bone Marrow: MGG Stain Reveals Diverse Cellular Morphology (x400 Magnification)
MGG staining, a cornerstone of hematopathology, employs a combination of dyes to vividly differentiate various cell types within bone marrow. This staining technique enables the visualization of the distinct morphological features of various cells, including myeloid precursors, erythroid progenitors, lymphocytes, and plasma cells.


To assess the bone marrow aspirate morphology accurately, prior knowledge of the patient’s history and also clinical indication for the procedure is necessary.

Microscopy examination usually covers 10X magnification, 40X magnification as well as 100X (oil immersion) magnification assessment.

Under 10X objective magnification, things to note include:

  • Hypercellular or hypocellular bone marrow fragment
  • Normal or diluted or hypercellular cell trails
  • Number and morphology of megakaryocytes available
  • Presence of abnormal cell clumps are suggestive of marrow infiltration

Under 40X objective magnification, things to note include:

  • Whether the erythropoiesis are normoblastic, megaloblastic or dysplastic in nature
  • Presences of all stages of normal maturation for the myeloid and lymphoid lineage cells including myeloblasts and lymphoblasts
  • Presence of normal or abnormal plasma cells and macrophages and whether their number is increased. 
  • Presence of any metastatic cells.

Related Diseases

ABO RhD Blood Grouping Tube Method

ABO RhD Blood Grouping Tube Method

Introduction The ABO and RhD blood groups are two of the most important systems for classifying human blood. They are determined by the presence or absence of specific antigens on the surface of red blood cells. The ABO Blood Group System The ABO blood group system is...

Glucose-6-Phosphate Dehydrogenase (G6PD) Fluorescent Spot Test 

Glucose-6-Phosphate Dehydrogenase (G6PD) Fluorescent Spot Test 

Introduction The G6PD fluorescent test is a rapid and reliable method for diagnosing G6PD deficiency. The test involves measuring the activity of G6PD in a sample of red blood cells. A low level of G6PD activity indicates a deficiency.  Glucose-6-phosphate...