Polycythemia vera (PV) is an acquired myeloproliferative disorder characterized by an elevated absolute red blood cell mass caused by uncontrolled red blood cell production, frequently associated with uncontrolled white blood cell and platelet production.

Severely increased amount of excretion of protein in the urine, defined as 3.5 grams per day or more in adults and 40 mg per meter-squared body surface area per hour in children.