apheresis, aphaeresis (singular); aphereses, aphaereses (plural)

1. The process of removing a specific component from blood and returning the remaining components to the donor, in order to collect more of one particular part of the blood than could be separated from a unit of whole blood: "Apheresis (af uh REE sis) takes longer than a whole blood donation which usually takes about 10-20 minutes to collect the blood, while an apheresis donation may take about one to two hours."
2. In linguistics, apheresis (uh FER i sis) is the omission at the beginning of a word as in "coon" for "raccoon"; "till" for "until"; "squire" for "esquire"; "count" for "account"; or "special" for "especial".

Separation of one or more kinds of cells (leukocytes, platelets, etc.) from whole blood with the return of other blood cell constituents to the patient or donor: "Cytapheresis is accomplished with an instrument that uses centrifugation to separate the cells into different layers based on the differences in cell density (displacement) or drag coefficients in a current (elutriation)."

The withdrawal of blood, then the separation and retention of red blood cells, and a retransfusion of the remainder back into the donor.

To harvest of a type of white blood cells filled with microscopic or little sacs containing enzymes, compounds that digest microorganisms (neutrophils, eosinophils, and basophil).

A method of obtaining supplies of white blood cells from a compatible donor for use in the treatment of an otherwise uncontrollable infection in a patient with acute leukemia.

Separation and removal of lymphocytes from the withdrawn blood, with the remainder of the blood retransfused back into the donor.

The selective separation and removal of plasma and lymphocytes from withdrawn blood, the remainder of the blood then being retransfused back into the donor.

A procedure designed to deplete the body of blood plasma (the liquid part of the blood) without depleting the body of its blood cells: "With plasmapheresis, the whole blood is removed from the body, the plasma is separated from the cells, the cells are suspended in saline, a plasma substitute or donor plasma), and the reconstituted solution may be returned to the patient."

"This procedure of plasmapheresis is done in a clinic or a hospital and is used to remove excess antibodies from the blood in lupus, multiple sclerosis, multiple myeloma, etc."

"Plasmapheresis carries with it the same risks as any intravenous procedure. The risk of infection increases with the use of another donor's plasma, which may carry viral particles despite screening procedures."

Removal of unwanted or pathological components from a patient's blood by means of a continuous-flow separator: "The therapeutic apheresis is similar to the process of hemodialysis, because detoxified blood is returned to the patient."

"The removal of cellular material is termed cytapheresis; leukapheresis describes the removal of leukocytes only. Plasmapheresis, also called plasma exchange, involves removal of noncellular materials."

Therapeutic aspharesis has been used to treat blood hyperviscosity, cold agglutinin hemolytic anemia, posttransfusion purpura, thkrombotic thrombocytopenic purpura, myasthenia gravis, sickle cell anemia, Guillain-Barre syndrome, familial hypercholesterolemia, and even certain drug overdoses."

The selective separation and removal of platelets (thrombocytes) from withdrawn blood, the remainder of the blood then being retransfused into the donor.