Rarely erythrocytes may take on a crescent appearance because of large vacuole.


Selenoid = crescent moon-shaped


Synonym: corps en demi-lune



(1) The peripheral blood smear shows crescent-shaped erythrocytes larger than adjacent normal erythrocytes

(2) The erythrocytes are very light in color (due to decreased hemoglobin concentration).

(3) The horns of the crescent run around a clear vacuole.


Cuadra demonstrated:

(1) The selenoid bodies are formed when the blood is mechanically spread over the surface of the glass slide.

(2) The appearance of the bodies is dependent on the amount of lipid in the plasma, with the number increased after a fatty meal.


It is necessary to exclude sickle cell and iron deficiency anemia.


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