Megakaryocytes in the bone marrow

Norm
Adults 50–100 ×106/l
Children (5 months – 4 years) 106–130× 106/l

Bone marrow
Bone marrow. Counting after hemolysis induced by vinegar solution

In bone marrow, megakaryocytes are counted separately from a blood smear examination. At the same time, along with the number of megakaryocytes, the cytozosis of bone marrow (number of myelocytes) is determined. In thrombocytopenic pathologies, the secretion of functionally active and inactive megakaryocytes (the latter do not show signs of platelet production in the cytoplasm) may have a certain significance. An approximate number of megakaryocytes can also be assessed by examining a bone marrow smear. The number of megakaryocytes in the marrow increases in case of polycythemia, chronic myeloid leukemia, myelofibrosis. Megakaryocytosis in the bone marrow occurs in patients with liver cirrhosis with hypersplenism. Thrombocytopenia in the periphery can cause a compensatory increase in the number of megakaryocytes in the bone marrow. An exception is made by myelophthisic aplastic processes. In these cases, the number of megakaryocytes in the bone marrow decreases along with a decrease in the number of platelets in the periphery.

The number of megakaryocytes in the bone marrow also increases in immune thrombocytopenic purpura. In this case, when observing megakaryocytes under a microscope, the process of platelet formation is slowed down. Sometimes platelet production in megakaryocytes is not visible at all. However, this feature is still a subjective evaluation by the laboratory physician, which may also depend on how the preparation was stained.

Source | Handbook of Basic Laboratory Tests | Doctor of Medical Sciences Gintaras Zaleskis