Polycythemia (also known as polycythaemia, polyglobulia and Erythrocytosis) is a disease state in which the hematocrit (the volume percentage of red blood cells in the blood) and/or hemoglobin concentration are elevated in peripheral blood. It can be due to an increase in the number of red blood cells ("absolute polycythemia") or to a decrease in the volume of plasma ("relative polycythemia"). Polycythemia is sometimes called erythrocytosis, but the terms are not synonymous, because polycythemia describes any increase in red blood mass (whether due to an erythrocytosis or not), whereas erythrocytosis is a documented increase of red cell count. The emergency treatment of polycythemia (e.g., in hyperviscosity or thrombosis) is by phlebotomy (removal of blood from the circulation). Depending on the underlying cause, phlebotomy may also be used on a regular basis to reduce the hematocrit. Myelosuppressive medications such as hydroxyurea are sometimes used for long-term management of polycythemia. Absolute polycythemia
The overproduction of red blood cells may be due to a primary process in the bone marrow (a so-called myeloproliferative syndrome), or it may be a reaction to chronically low oxygen levels or, rarely, a malignancy. Alternatively, additional red blood cells may have been received through another process—for example, being over-transfused (either accidentally or, as blood doping, deliberately) or being the recipient twin in a pregnancy, undergoing twin-to-twin transfusion syndrome. Primary polycythemia
Primary polycythemias are due to factors intrinsic to red cell precursors.
Classified may refer to:

General
Classified information, material that a government body deems to be sensitive
Classified advertising or "classifieds"

Music
Classified (rapper) (born 1977), Canadian rapper
The Classified, a 1980s American rock band featuring Steve Vai
Classified Records, an American record label

Albums
Classified (Bond album), 2004
Classified (Classified album), 2013
Classified (Sweetbox album), 2001
Classified, by James Booker, 1982

Songs
"Classified", by C. W. McCall from Wolf Creek Pass, 1975
"Classified", by the Orb from Metallic Spheres, 2010
"Classified", by Pete Townshend from the compilation Glastonbury Fayre, 1972
"Classifieds", by the Academy Is... from Almost Here, 2005

Other media
Classified (1925 film), an American silent film
Classified: The Edward Snowden Story, a 2014 Canadian film
Classified: The Sentinel Crisis, a 2005 video game for the Xbox

See also
Classification (disambiguation)
Classifier (disambiguation)