The blood platelet or thrombocyte concentration varies between individuals but remains rather constant in each individual. The reference range is 150-360 × 109 /l.
Thrombocytosis can be classified into two categories: primary thrombocytosis, i.e. thrombocytosis related to myeloproliferative diseases, and secondary or reactive thrombocytosis.
In addition, it should be kept in mind that the reference range follows the Gaussian curve, i.e. 2.5% of healthy people have platelet levels exceeding the reference range. In most such cases, the platelet level exceeds the upper reference limit only slightly.
In reactive thrombocytosis, platelets rarely cause problems, and treatment of the underlying disease will correct platelet levels.
Secondary thrombocytoses: acute or chronic haemorrhage, over-compensation in the recovery phase of thrombocytopenia, connective tissue disorders, infections, intense physical exercise, childbirth, iron deficiency, haemolytic anaemia, a sequel of splenectomy, neoplastic diseases, reactions to medications, sequelae of operations
Treatment
In secondary thrombocytosis, treatment of the primary disease; treatments to lower the platelet count are usually not needed.
As in myeloproliferative diseases thrombocytosis is associated with an increased risk of thrombosis and bleeding, a haematologist or an internist should be consulted even in cases with no symptoms.
A haematologist or an internist should be consulted if the cause of thrombocytosis remains unclear.