Primary polycythemia (myeloproliferative disorders)<unk> 
Essential thrombocytosis (ET)
Chronic myelogenous leukemia (CML)
Leukemoid Reaction
Myelofibrosis
Secondary polycythemia (due to increased EPO)
Chronic hypoxemia (e.g. COPD, physiologic altitude adaptations or chronic mountain sickness)
Carboxyhemoglobin (chronic smokers)
Renal cyst or hydronephrosis
EPO-secreting tumors (RCC, hepatocellular carcinoma)
Anabolic steroid abuse
Abnormal hemoglobins<unk> 
Essential thrombocytosis (ET)
Chronic myelogenous leukemia (CML)
Leukemoid Reaction
Myelofibrosis
Chronic hypoxemia (e.g. COPD, physiologic altitude adaptations or chronic mountain sickness)
Carboxyhemoglobin (chronic smokers)
Renal cyst or hydronephrosis
EPO-secreting tumors (RCC, hepatocellular carcinoma)
Anabolic steroid abuse
Abnormal hemoglobins
Polycythemia vera
Primary polycythemia 
Aplastic anemia
Essential thrombocytosis
Essential thrombocytosis 
Myelofibrosis
Chronic myelogenous leukemia 
Immune thrombocytopenic purpura