Red Cell Characteristics Related to Shape
Another example of a target cell (or codocyte) is seen in the center of this slide. Notice that the hemoglobin in the center of this cell is somewhat lighter in appearance than in the previous slide. A second codocyte can be seen in the upper left portion of the slide. Codocytes appear in conditions which cause the surface of the red cell to increase disproportionately to its volume. This may result from a decrease in hemoglobin, as in iron deficiency anemia, or an increase in cell membrane.
Target cells have excess membrane cholesterol and phospholipid and decreased cellular hemoglobin. Examples of other conditions in which target cells may be present include thalassemias, hgb C disease, post splenectomy and obstructive jaundice. Since their presence can be the result of an in vitro artifact, their value in clinical diagnosis is limited.