Purpura: Small spots on the skin formed by subcutaneous effusion of blood.
: A condensation and reduction
of the cell and its nucleus.
Reduced Hemoglobin: A combination of hemoglobin and carbon dioxide that is found
in venous blood.
Reticulocyte: A red blood cell showing a reticulum or network when stained with vital
dyes (for example, brilliant cresyl blue). The stage between the nucleated red cell and
the mature erythrocyte.
Reticulocytosis: An increase above normal values of reticulocytes in peripheral blood.
RNA: Ribonucleic acid.
Rouleaux Formation: The arrangement of red cells with their flat surfaces facing, in
which they appear as figures resembling stacks of coins.
Rubricyte: Polychromatophilic normoblast.
Sedimentation Rate, Erythrocyte (ESR): The rate at which red cells will settle out in
their own plasma in a given time under controlled conditions.
Serum: The fluid portion of the blood, after clot formation.
Shift to the Left: A term used to designate that condition in which the immature forms
of the neutrophils are increased above their normal number.
Shift to the Right: Increase in mature, pyknotic, and hypersegmented neutrophils.
Sickle Cell: A sickle- or crescent-shaped erythrocyte.
Sickle Cell Anemia: This is a hereditary and familial form of chronic, hemolytic anemia
essentially peculiar to Negroes. It is characterized clinically by symptoms of anemia,
joint pains, leg ulcers, acute attacks of abdominal pain and is distinguished
hematologically by the presence of distinct hemoglobin, peculiar sickle-shaped and oat-
shaped red corpuscles, and signs of excessive blood destruction and active blood
Smudge Cell: A ruptured white cell; also basket cell, or degenerated cell.
Spherocyte. A red blood cell that is more spherical, smaller, darker, and more fragile
Stasis: A stoppage of blood flow.