Some New Model Geometries for Sickled Erythrocytes

Proposed model geometries are described for six types of flattened sickled erythrocytes. These new types occur with some frequency in blood smears of patients with sickle cell disease. The six types of cells are designated as five-pointed star, witch, hypocycloid, deltoid, astroid, and semi-circular. Formulae are provided for the volume and surface area of each type and a figure showing the profile of each is included. Measurements of actual sickled cells in vitro could be used to find values for the volume and surface area of each type of cell by using parameter values for the appropriate model geometry. These would give close approximations that could be useful in clinical therapies and laboratory investigations for sickle cell anemia. Surface area to volume ratios can also be found to a close approximation for each cell type.