Helmet cells in microangiopathic hemolytic anemia

Peripheral smears from two patients with microangiopathic hemolytic anemia, showing a number of red cell fragments (ie, schistocytes), some of which take the form of combat (arrow), bicycle (arrowhead), or football (short arrow) "helmets." Microspherocytes are also seen (dashed arrows), along with a nucleated red cell (thick arrow).

High-power view of a normal peripheral blood smear. Several platelets (arrowheads) and a normal lymphocyte (arrow) can also be seen. The red cells are of relatively uniform size and shape. The diameter of the normal red cell should approximate that of the nucleus of the small lymphocyte; central pallor (dashed arrow) should equal one-third of its diameter.