•Red blood cells (erythrocytes) are biconcave disks with a diameter of 7-8 microns, which is similar to the size of the nucleus of a resting lymphocyte.  In normal red blood cells, there is an area of central pallor that that measures approximately 1/3 the diameter of the cell.  Though reference ranges vary between laboratories and in different age groups, normocytic red blood cells typically have a mean corpuscular volume (MCV) between 80-100 fL.