Hematocrit dependence of the Cole-Cole parameters of human blood

Abstract

The specific impedance of human erythrocytes suspended in plasma was measured in the frequency range from 100 kHz to 1 MHz, in samples from nine healthy donors. These samples were diluted with 0.9% saline in different volumes to obtain samples with different hematocrit values, ranging from 31 to 50. The complex impedance was measured as a function of frequency and then fitted into Cole-Cole diagrams, with rms errors of less than 0.5%, using a LMS algorithm. Data were interpreted in terms of an equivalent resistor-capacitor circuit. In this hematocrit range, Cole-Cole parameters R/sub e/, R/sub i/, F/sub c/, and a in turn are shown to be a linear function of hematocrit (0.98<r<1). As the concentration of red blood cells in blood samples is augmented, the intracellular conductivity is increased while extracellular conductivity is reduced, and Cole-Cole plots are shifted upwards to the right, in the complex plane, indicating a higher /spl alpha/ and a lower f/sub c/. Cole-Cole parameters might be a potential index for evaluating blood in clinical applications.