Background Information of Stomatocytes
Stomatocytes are erythrocytes that have a slit-like central pallor. In three dimensions, the stomatocyte is actually bowl-shaped, as the cell has lost its biconcave morphology due to a membrane defect. Most cases of stomatocytosis are due to alteration in permeability, leading to an increase in red cell volume, hence reducing the central pallor. Stomatocytes form at a low blood acidic pH as seen in exposure to cationic detergents, and in patients receiving phenolthiazine or chlorpromazine. Stomatocytosis can be an inherited or acquired condition.
In hereditary stomatocytosis, mild anemia and findings of on-going hemolysis may be evident if the condition presents as a clinical problem at all. Individuals who possess the Rh null phenotype have osmotically fragile red cells, which take the form of stomatocytes. Individuals with this phenotype tend to experience varying degrees of chronic hemolytic anemia.
*Note: Unless >10% RBCs are stomatocytes, their presence is probably artefactual if the blood smear is too thick.
Stomatocytes are RBCs that are almost identical in size with their normal counterparts but with a slit-shaped central pallor. Some times it is more densely stained than the normal RBCs.