Recent results for low‐frequency scattering by correlated random distributions of nonspherical particles averaged over orientation are applied to invert ultrasonic data for red blood cell suspensions under different flow conditions. The inversion procedure isolates a correlation parameter (c) representing a process in which the volume fraction (w) of particles increases linearly, and also a cell population parameterP. Reduced data records of scattering versus hematocrit are compared withS(c;w)P, where the generalized fluctuation functionSis proportional to the variance in particle number, andPis proportional to the backscattering cross section of an isolated particle. The peak scattering for the different flow processes occurs at values ofwranging from about 0.15 for the most uniform to 0.25 for the least, corresponding tocvalues of about 2.1 to 0.4, as compared withw≊0.13 andc=3 for hard (repulsive at contact) spheres or aligned ellipsoids. The lower values ofcsuggest weaker repulsion between the deformable cells and effective interparticle attraction (aggregative trends), andc≊2 may also involve flow alignment of the discoids.