99.5 Good Specimen HE-36 is an example of a target cell or codocyte. The cell shows a central hemoglobinized area within a surrounding area of pallor, which in turn is surrounded by a peripheral hemoglobinized zone. Several other target cells are present within the illustrated field. Target cells may be seen in hemoglobinopathies, in liver disease, in patients who have had a splenectomy, as is the case in this exercise and may also be seen as an artifact of slow drying of the blood smear in a humid environment. 99.3 Good Specimen HE-37 illustrates normal platelets.
Platelets are the smallest normal cellular element seen in blood smears.
They are round to ovoid fragments of megakaryocyte cytoplasm which are 1.5 to 4 m in diameter. They are anucleate and have pale blue to clear cytoplasm which contains several red-purple granules which are often aggregated centrally. In the process of making blood smears, smaller elements such as platelet sometimes come to overlie larger elements such as erythrocytes. Recognition of this phenomenon is important because the appearance can be confused with an intra-erythrocyte infectious agent such as Babesia or Plasmodia. This is of particular concern in a patient who lacks functional splenic tissue as such infections tend to have a fulminant and potentially fatal course in such a host.