Histopathological image representing a bone marrow aspirate in a patient with essential<unk> <unk>  is a condition of high platelet (thrombocyte) count in the blood. Normal count is in the range of 150x109 to 450x109 platelets per liter of blood, but investigation is typically only considered if the upper limit exceeds 750x109/L. When the cause is unknown, the term<unk>  is used, as either primary<unk>  or essential<unk> . The condition arises from a fault in the bone marrow cells leading to over-production of platelets but the cause of the fault is unknown, and this type is not common. When the cause is known such as another disorder or disease, the term thrombocytosis is preferred, as either secondary or reactive thrombocytosis. Reactive thrombocytosis is the most common type and though it can often have no symptoms it can sometimes predispose to thrombosis. In contrast, thrombocytopenia refers to abnormally low blood platelet numbers in the blood.
Thrombocythemia
Leukostasis
Thrombocytopenia
Red cell agglutination
Leukocytosis
Lycopenemia
Reticulocytosis
Cytopenia