The invention discloses an apparatus and a method for determining the
volume of individual red blood cells or other particles that are suspended
in liquids. The sample is disposed into an optical cuvette suitable for
microscopic analysis. An absorbing dye is added that does not leak into
the cells, and that is able to absorb light at wavelengths that are only
weakly absorbed by the cells. The cell volume is determined using
transmitted light intensity values measured (i) in a first area comprising
a single cell, (ii) in a second area close to that cell, and (iii) in said
second area, after changing the cuvette thickness by a known amount.
