Evaluation of microcytic anemia.

Anemia is defined as a reduction in red blood cell mass or hemoglobin concentration in blood. It is statistically differentiated from normal states as a hemoglobin concentration or hematocrit 2 SD below the mean for the healthy population adjusted for age and sex. Anemias may be classified based on the morphologic function of red blood cells and their size on a peripheral blood smear. Subcategories are microcytic, normocytic, and macrocytic anemias, but these are not mutually exclusive. In infants and children, the most common form of anemia is microcytic. A detailed history and physical examination with appropriate laboratory test results can help detect the correct cause of anemia in most patients. The objective of this article is to aid physicians taking care of children in conducting a proper evaluation to identify the correct cause of microcytic anemia.