This document provides detailed information on polycythemia vera (PV), including its pathophysiology, clinical features, diagnosis, differential diagnosis, and laboratory evaluation. PV is a myeloproliferative neoplasm characterized by excessive red blood cell production. Key points: PV results from abnormal stem cell clone producing increased red blood cells, white blood cells, and platelets. Symptoms include bleeding, thrombosis, pruritus, headache, and visual issues due to hyperviscosity. Diagnosis requires elevated red blood cell count/mass and meeting criteria set by the Polycythemia Vera Study Group or WHO guidelines, which may include genetic testing for JAK2 mutation. Differential diagnosis excludes secondary causes of polycy