What characterizes polycythemia vera (PV)?

Polycythemia vera (PV) is specifically characterized by an absolute increase in total red cell mass. This condition is a myeloproliferative neoplasm, meaning that it involves the overproduction of blood cells due to uncontrolled proliferation within the bone marrow. In PV, the body produces more red blood cells than normal, which leads not only to an increase in red blood cell count but also to higher hemoglobin and hematocrit levels. This excess red cell mass contributes to increased blood viscosity, which can lead to complications such as thrombosis.

Understanding the distinct nature of PV is crucial, as it differentiates this condition from those characterized by reduced cell production or related issues, such as anemia or other hematological disorders that involve decreased blood components.