Investigation of poikilocytic normochromic normocytic anemia. 2. Spiculated forms.

Spiculated poikilocytes occur in several different forms. Each form is associated with certain types of diseases or conditions. Identification of a dominant form in a blood smear provides a clue to diagnosis. Helmet cells, triangular cells, and schistocytes most commonly suggest disease in the microvasculature. "Bite" cells are usually a product of drug-induced hemolysis. Keratocytes are variants of helmet cells and therefore occur in the same clinical circumstances as helmet cells. Echinocytes are usually artifacts; true echinocytosis is rare and associated mainly with uremia. Acanthocytosis occurs most commonly after splenectomy but may be encountered in severe liver disease.