Scattering of a laser beam on a wet blood smear and measurement of red cell size distribution

We report an automated laser system that allows the red cell size distribution to be measured. Experiments are performed on laser light scattering by a suspension of oriented red blood cells (a wet blood smear). Based on an analysis of the angular distribution of light intensity in the diffraction pattern, we have restored the red cell size distribution. The average diameter of a red blood cell is determined with an error of less than 1%, and the spread of red blood cells in size – with an error of about 20%. We discuss the problems of photometry and processing of diffraction patterns, preparing blood samples and data processing algorithms, including methods for solving the inverse scattering problem.