Shown above is an image of hypochromic microcytic anaemia. This patient had iron deficiency anaemia. Microcytosis is presence of small erythrocytes and hypochromia presence of erythrocytes that are poorly haemoglobinized. The nucleus of a small lymphocyte, the cell in the centre of the image, is a good guide to the size of erythrocytes on a peripheral smear. The nucleus has a diameter of 8.5 µm and a normal erythrocyte a diameter of 7.5 µm. The erythrocytes in in the image are substantially smaller than the lymphocyte nucleus. Erythrocytes have a central pale staining area which occupies about one third of erythrocyte diameter. As the cells get less haemoglobinized the central pale staining area increases. Many of the erythrocytes in the image above have a pale staining area occupies all but a thin rim at the periphery. In others, the pale staining area is increased. The erythrocyte sizes vary. Anisocytosis, increased variation in erythrocyte size, a feature of iron deficiency anemia, is evident in the image.