Some problems in the mathematical modelling of erythrocyte sedimentation

The rate at which red blood cells fall in vitro is used as a common clinical test, amongst others, for a number of pathological conditions. The use of this test is cast into doubt when one finds flaws in the underlying models and confusion over fundamental issues such as the aggregation of the red blood cells. Both of these deficiencies are evident in an otherwise innovative publication by Huang et al. (1971). In examining the mathematics of this relatively unknown study, it is found that the Huang model resembles certain moving-boundary problems. The consequences of this observation are discussed.