CORE LABORATORY
Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are also elevated in most cases. Since red blood cells are overproduced in the marrow, this leads to abnormally high numbers of circulating red blood cells (red blood mass) within the blood. Consequently, the blood thickens and increases in volume, a condition called hyperviscosity. Thickened blood may not flow through smaller blood vessels properly.1
The symptoms of polycythemia vera usually develop slowly over many years. Often, the disorder is found incidentally on a blood test as part of a routine exam before noticeable symptoms occur. Occasionally, affected individuals may report vague, nonspecific symptoms that eventually lead to diagnosis of the disorder.1
A variety of symptoms can occur in individuals with polycythemia vera including nonspecific symptoms such as headaches, fatigue, weakness, dizziness or itchy skin; an enlarged spleen (splenomegaly); a variety of gastrointestinal issues; and the risk of blood clot formation, which may prevent blood flow to vital organs.1
Polycythemia vera is caused by a malignant change in the genetic material (DNA) within a single cell of the bone marrow (clonal disorder). Bone marrow is the soft, spongy material found inside bone where most blood cell production occurs. The underlying reason why this malignant change occurs is unknown.1
