Question: what's the difference between polycythemia and polycythemia vera

title: Polycythemia
text: Primary polycythemias are due to factors intrinsic to red cell precursors . Polycythemia vera ( PCV ) , polycythemia rubra vera ( PRV ) , or erythremia , occurs when excess red blood cells are produced as a result of an abnormality of the bone marrow . Often , excess white blood cells and platelets are also produced . PCV is classified as a myeloproliferative disease . Symptoms include headaches and vertigo , and signs on physical examination include an abnormally enlarged spleen and / or liver . In some cases , affected individuals may have associated conditions including high blood pressure or formation of blood clots . Transformation to acute leukemia is rare . Phlebotomy is the mainstay of treatment . A hallmark of polycythemia is an elevated hematocrit , with Hct > 55 % seen in 83 % of cases . A somatic ( non-hereditary ) mutation ( V617F ) in the JAK2 gene is found in 95 % of cases , though also present in other myeloproliferative disorders .