Normal erythrocytes are round disks about 7.5μm in diameter.The central one third is paler than the periphery because of the discoid shape of the erythrocyte. The picture above is a 40X image that shows the uniformity of size and staining of normal erythrocytes. Can one say that the
se cells are 7.5μm in diameter? They could all be 10μm or be 6μm. Is it possible to known about the size of erythrocytes using an unsophisticated laboratory microscope?
The small lymphocyte comes to the rescue! The size of the small lymphocyte nucleus is approximately 8.5μm and it does not vary significantly with disease. The picture above is a 100X image comparing the normal erythrocyte with a small lymphocyte. The cells are slightly smaller than a small lymphocyte. The uniformity of size and that of the pale staining area is evident. Microcytes are smaller erythrocytes and macrocytes larger erythrocytes. Hypochromia is increase in the pale staining area and indicates decreased content haemoglobin. Anisocytosis is increased variability in erythrocyte shape.
All About Blood 