Echinocyte comes from the Greek word meaning “sea urchin,” which relates to its shell-like appearance. Echinocytes are reversible, meaning that this alteration can be the result of the cell’s environment, pH of the medium (including the glass slides on which blood smears are made), the metabolic state of the cell and the use of some chemical substances. An example of an echinocyte can be seen in the center of this slide. Notice the projections (10-30 can be seen) are rounded and evenly spaced around the cell. Acanthocytes have irregularly spaced thorn-like projections. An echinocyte is shown left of the B in this photomicrograph. A polychromatophilic cell is seen just above the echinocyte.