Abstract: An apparatus and method for measuring the volume and hemoglobin concentration of individual red blood cells in a whole blood sample provides for isovolumetrically sphering the red blood cells of the sample using a sphering reagent and forming a stream of individual, spaced-apart cells sheathed in an electrolytic liquid in a flow chamber. The red blood cells in the stream are passed through a light scattering channel in which the intensity of light scattered by each cell into a preselected angular interval in the forward direction is measured. Each cell in the stream is also passed through a resistance pulse sizing aperture for measuring the volume of the cell.

Abstract: A method and apparatus are disclosed for determining the volume and hemoglobin concentration of an isovolumetrically sphered red cell by passing the cell through a beam of monochromatic light to produce one forward light scattering pattern, and measuring the forward light-scattering pattern at two selected angular intervals to generate signals S1 and S2, respectively. The first angular interval is selected to span the angular region within which the first maxima of the light scattering patterns of the cells having volumes in the physiological range are expected to fall. The second angular interval is selected which begins above the upper limit of the first angular interval and below the second maximum of the scattering pattern of the cell having the largest volume in the physiological range and which extends to an angle at which the secondary maxima are reduced substantially to zero in comparison to the magnitude of the first maximum.