Treat underlying disease.
81mg ASA PO daily.
If high risk  for thrombotic event (>60 yrs, history of thrombosis, or known JAK2 mutation), consider 15mg/kg hydroxyurea PO daily.  Consult if available.
Second line agents include interferon-α, anagrelide, and pipobroman.
Anticoagulation with LMWH.
81mg ASA PO daily.
Consult heme/onc
Consider 3-5 million U interferon-α SQ daily if <40 years old.  15mg/kg hydroxyurea PO daily if >40 years old.  Goal platelet count <400,000/microL.
Platelet apheresis if platelet count >800,000/microL.
Discontinue antiplatelet medications.
Consult.
Consider 3-5 million U interferon-α SQ daily if <40 years old.  15mg/kg hydroxyurea PO daily if >40 years old.  Goal platelet count <400,000/microL.
Thrombocytosis
Acute blood loss
Thrombocytopenia
Acute hemolytic anemia
Polycythemia
Iron deficiency anemia
Leukopenia
Treatment of vitamin B12 deficiency