The Normal Megakaryocyte Concentration in Aspirated Human Bone Marrow

1. A practical chamber method has been devised for enumerating the megakaryocyte concentration of aspirated bone marrow.

2. Marrow aspirations from 23 healthy young adults had a mean megakaryocyte concentration of 4.0 ± 1.1 per 10,000 total nucleated cells or 6.1 ± 1.6 per 10,000 granulocytes.

3. Of the three principal cell types in marrow, i.e. granulocytes, erythrocytes and lymphocytes, the megakaryocyte content seemed to parallel most closely the granulocytes.