Microcytic Index

Microcytic anemia is a frequently encountered medical abnormality, and it may be caused by iron deficiency anemia, a hemoglobinopathy (e.g. beta-thalassemia), sideroblastic anemia, or possibly anemia of chronic disease/inflammation. Iron deficiency anemia and beta-thalassemia account for a vast majority of microcytic anemias. Distinguishing these tests by the red blood cell indices in a complete blood count has some clinical utility, and could direct a physician to either iron therapy, confirmatory iron studies, confirmatory hemoglobin electrophoresis, or thalassemia therapy. Many authors have proposed differential variables or computations (indexes), but no one proposal can universally distinguish these two entities.

The microcytic index is a global scoring system that takes into account 19 different variables including red cell indices and many calculated indices. The result is a number between 0 and 100. This application will calculate the microcytic index, and give an interpretation based on the result.

Since this index is based on indices that are imperfect, this result is imperfect. It is not intended for non-microcytic patients or infants under the age of two weeks. Correlation with blood smear review is recommended to assess for hypochromia and exclude hemoglobin C abnormalities or sideroblastic anemia. Although many of the components have been studied, this index has not been tested in a published clinical study. Nevertheless, it may be a valuable tool in the assessment of microcytic anemia.