APPEARANCE: These are red blood cells that contain a bright white center encircled by a dark ring that makes it look like a target. The center of the cell does not pulsate or fade in and out, it remains static and bright white.
SUGGESTED CAUSE: May be caused by increased cholesterol and lecithin content, bile insufficiency, liver disease, spleenectomy or anemia. The lack of pulsation in the middle of a target cell as opposed to a healthy specimen is due to the fact that the cell membrane has collapsed on itself. This is thought to be due to a lack of iron/hemoglobin. The picture on the right is a more 3 dimensional perspective which better shows the severe concave, donut like nature of a target cell.
POSSIBLE SIGNS: Anemia, tired, low energy.
MED PERSPECTIVE: Codocytes are erythrocytes that exhibit a dark circular "target" pattern. Marked elevations of target cells is the result of a shift in the exchange equilibrium between the red cells and cholesterol. Conditions that reduce lecithin-cholesterol acetyltransferase production, or interfere with enzyme mechanisms of performance results in elevation of red cell cholesterol and serum phospholipid ratios. Further, the bile salts content ratio in the plasma can affect the exchange between cholesterol and the red cell membrane.
Target cells are seen in hypochromic anemia, liver disease and on occasion following spleenectomy. Erythrocytes with this configuration are cells lacking iron, therefore any disease process which affects red cell iron absorption may produce target cells. Disruption of hepatic lecithin-cholesterol acetyltransferase production in the alteration of bile acid concentrations due to biliary obstruction can account for increased red cell lipid deposition. The spleen also influences the regulation of erythrocyte lipid content.
ADD'L TESTS: CBC with differential, serum iron, serum transferrin, serum ferritin, and liver profile (SGPT, GGT, SGOT, LDH, Alkaline phos-phatase).
Note: Hypochromic anemia red blood cell morphology is often connected with whiter central areas in the RBC as examined under phase contrast. Sometimes you may see RBCs that look like bowling pins at the bowling alley. This is often associated with thalassemia or Mediterranean anemia which is due to specific defects in globin synthesis with a resultant deficiency in synthesis of normal hemoglobin.