phlebotomy The field of obtaining blood from a vein. Phlebotomy is done by puncturing a vein with a needle. Phlebotomy may be done in order to obtain blood for diagnostic tests or to remove blood for treatment purposes (for example, to relieve iron overload in hemochromatosis).
phlebotomist A person who draws blood for diagnostic tests or to remove blood for treatment purposes.
phlebo- Prefix meaning vein, as in phlebitis (inflammation of the veins) and phlebotomist (a person who draws blood from veins).
phlebitis Inflammation of a vein. With phlebitis, there is infiltration of the walls of the vein and, usually, the formation of a clot (thrombus) in the vein (thrombophlebitis). Phlebitis in a leg, for example, causes the leg to swell with fluid (edema). Phlebitis can be superficial and not very serious, or it can be deep…
phimosis A condition in which the foreskin of the penis is too tight to be pulled back to reveal the glans. This usually causes no problems and nothing needs be done. If phimosis causes obstruction of the urinary stream, meaturia (blood in the urine), or pain, this can require surgery to relieve the phimosis. Circumcision…
philtrum The area from below the nose to the upper lip. Normally the philtrum is grooved. In fetal alcohol syndrome, the philtrum is flat.
Philadelphia chromosome Abbreviated Ph, the hallmark of chronic myeloid leukemia (CML), a small chromosome 22 that was shortened in a reciprocal exchange of material with chromosome 9. This translocation occurs in a cell in the bone marrow and causes CML. It is also found in a form of acute lymphoblastic leukemia (ALL). On a molecular…
pheromone An agent secreted by an individual that produces a change in the sexual or social behavior of another individual of the same species; a volatile hormone that acts as a behavior-altering agent.
pheresis A procedure in which the blood is filtered and separated, and a portion is retained, with the remainder being returned to the individual. There are various types of pheresis. For example, in leukapheresis, the leukocytes (white blood cells) are removed; in plateletpheresis, the thrombocytes (blood platelets) are removed; and in plasmapheresis, the liquid part…
phenylketonuria, maternal See PKU, maternal.
phenylketonuria See PKU.
phenylalanine hydroxylase deficiency The inherited inability to normally process the amino acid phenylalanine, due to partial or complete deficiency of the enzyme phenylalanine hydroxylase. This deficiency is caused by mutation in the PAH gene on chromosome 12. Phenylalanine hydroxylase deficiency causes a spectrum of disorders, including classic phenylketonuria (PKU), variant PKU, and nonPKU elevation of…