High-resolution data on the geometry of red blood cells

Abstract

The need for accurate determination of the geometry of red blood cells is discussed. To overcome the difficulty of wave diffraction which casts a fuzzy border around any object in light microscopy and thus causing an uncertainty in measurements, the method of interference holography was used. Samples of human red blood cells were taken from 14 healthy subjects and the cell geometry was measured from photographs taken in a Leitz interference microscope of the Mach-Zender type. The images were analyzed as holographs. The method has a resolution of 0.02 μm. Statistical results on cell diameter, minimum and maximum thickness, surface area, volume and sphericity index, as well as the correlations between these parameters are reported. For the total samples collected, the average human red cell diameter was found to be 7.65 ± 0.05 μm (SEM), with a standard deviation of 0.67 μm. The mean values of the surface area and volume computed from holograms were 129.95 ± 1.03 μm² (SEM) and 97.91 ± 1.06 μm³ (SEM) respectively. The standard deviations of the area and volume were 15.86 μm² and 16.16 μm³ respectively. The correlation between diameter vs volume and diameter vs surface area are discussed. Applications of these data are illustrated. In the appendix the geometric parameters of the red cells of the rabbit are presented.