Hypochromia means that the red blood cells have less color than normal when examined under a microscope. This usually occurs when there is not enough of the pigment that carries oxygen (hemoglobin) in the red blood cells. The most common cause of hypochromia in the United States is iron deficiency. The cause of hypochromia should be evaluated.
Ginder GD. Microcytic and hypochromic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 163.