Heinz Bodies
Heinz bodies represent oxidized hemoglobin and can be observed as rounded protruberances which deform the red blood cells. They can readily be observed with a New Methylene Blue stain. Feline hemoglobin is particularly prone to oxidation when exposed to oxidative agents (especially acetaminophen which is toxic in cats!) because of the great number of amino acids possessing a sulfhydryl group (-SH) in this species' hemoglobin molecule. A small number of small Heinz bodies may be clinically without consequence in cats (generally < 10%, and usually in the order of 2-3%). However, when the Heinz bodies are larger and occur with greater frequency (affecting in excess of 20-30% of the circulating red blood cells), they may contribute to the development of hemolytic anemia.
