On the Suitability of Low-Cost Compact Instrumentation for Blood Impedance Measurements

This paper shows the feasibility of the blood analysis based on the electrochemical impedance spectroscopy (EIS) using compact low-cost instrumentations. This paper presents the measurement problem and some models for the interpretation of blood impedance spectra. The requirements for ad-hoc instrumentation are derived, and the implementation of a compact, low-cost, and reliable impedance measurement system operating in the frequency range 1 kHz-2.2 MHz is described, which is an improved version of the one presented in a previous work. To prove the potentialities of the EIS-based blood analysis, some parameters relevant to medical diagnosis such as hematocrit, erythrocyte sedimentation rate, and reactive oxygen species levels in blood are extracted from the impedance spectra measured with the two instruments. The presented results indicate that the application of low-cost compact systems for blood impedance measurements can reduce time and costs of the blood analysis and open new perspectives, especially for point-of-care diagnostics.

I. Introduction

The electrochemical impedance spectroscopy (EIS) is a widely used method for biomedical parameters identification and biological tissue behavior modeling. Charge production–recombination processes, media interaction, and phase changes in biological samples can be monitored, and corresponding suitable electrical models of some macroscopic phenomena can be derived directly through impedance measurements.