Diameters of erythrocytes of different ages measured by scanning electron-microscopy

Contradictory reports exist about the age-dependent changes of erythrocyte diameters. All the investigations were carried out using Coulter Counter, by which the erythrocytes are sucked through a glass capillary. The contact with a glass surface causes the cell to deform instantly. This explains the lack of accuracy of the measurements subsequently taken. We measured the size of red cells of different ages by scanning electron-microscopy, thus avoiding deformations. We found that the average diameter decreases with the age of the red cell. The mean diameter was 7.77 microns in young cells, 7.34 microns in middle-aged and 7.00 microns in old cells.