The Granulation Score (G-Score) for Neutrophils of Widell et al

 

The G-score can be determined on either the bone marrow or the peripheral blood smear. The G-scores for bone marrow and peripheral blood show a linear relationship, as shown in Figure 2 (Widell et al, page 118).

Neutrophilic Granulation	Grade
clearly visible granules covering the entire cytoplasm	3
faintly colored granules or with less than two thirds of cytoplasm covered	2
rare or few granules	1
agranular with no visible cytoplasmic granules	0

 

where:

• The criteria for Grade 1 was not described in the text but was shown in Figure 1 (Widell et al, page 116).

 

G-score =

= SUM(granulation grades for 100 neutrophils)

 

Interpretation:

• minimum G score: 0

• maximum G score: 300

• The normal G score is >= 255.

• A G score < 150 indicates extreme hypogranulation and tends to be seen in patients with bi- or tri-lineage dysplasia in the bone marrow.

• Patients with lower G scores tend to have an increased percentage of myeloblasts in the bone marrow biopsy.