Defined as a platelet count >450,000/microL.
Most common cause of<unk> , accounting for 85% of cases.
A reaction to another process, such as inflammation, infection, cancer, or iron deficiency.
Rarely causes complications even with extremely elevated platelet counts (>1,000,000/microL).
Accounts for 15% of cases
A primary problem that results from myeloproliferative disorders or myelodysplastic syndromes, such as essential thrombocytopenia or polycythemia vera.
Complications, such as bleeding and/or thrombosis, are more likely with AT than with RT so it is clinically important to differentiate reactive<unk>  versus autonomous<unk> .
There are no diagnostic studies to differentiate RT versus AT.
Thrombocytosis
Acute blood loss
Thrombocytopenia
Acute hemolytic anemia
Polycythemia
Iron deficiency anemia
Leukopenia
Treatment of vitamin B12 deficiency