Increased platelets on peripheral smear in essential thrombocythemia

Peripheral smear from a patient with essential thrombocythemia shows an increased platelet number and clumps of large, abnormal platelets.

High-power view of a normal peripheral blood smear. Several platelets (arrowheads) and a normal lymphocyte (arrow) can also be seen. The red cells are of relatively uniform size and shape. The diameter of the normal red cell should approximate that of the nucleus of the small lymphocyte; central pallor (dashed arrow) should equal one-third of its diameter.