Definition of Polycythemia vera (PV)

Polycythemia vera (PV) is characterized by an excessive production of blood cells due to a myeloproliferative disorder. This condition can progress into acute leukemia or a scenario where scar tissue replaces the bone marrow, known as myelofibrosis. A diagnosis of polycythemia vera requires an elevated red blood cell count and total RBC volume, with polycythemia being formally identified when these levels exceed the norm. For instance, hematocrit levels, which measure the percentage of red blood cells in the blood, typically range from about 42 to 52% in adult males and 37 to 48% in adult females. In those with polycythemia, these levels are significantly higher—over 52% in men and over 48% in women. Additionally, in 40 to 60% of cases, patients experience increased white blood cell counts and platelets, with vitamin B12 levels often being elevated as well.

Medical Definition & Meaning