Estimating the resistivity of the interior fluid of red blood cells using Fricke´s equation

Multifrequency (1 kHz-1 MHz) impedance of human blood, from 8 donors, for the hematocrit range from 36% to 43.5%, is measured using the true four-probe technique, Cole-Cole parameters, that are characteristic of blood, are used to model the equivalent electrical circuit. Results are then applied to Fricke´s theory of suspension of particles at f→0 and f→∞. Fricke´s equation, so far, has been widely used at f→0 In determining the shape factor for red cells or the hematocrit of blood samples. Here, it is shown that, solution of Fricke´s equation of suspension at f→∞ can be used in calculating the inside resistivity ρ_c of red cells. The authors suggest that ρ_c should replace the Cole-Cole parameter ρ_i. This parameter, together with Cole-Cole parameters might be a potential index for evaluating blood in clinical applications