Temperature Correction to Enhance Blood Glucose Monitoring Accuracy Using Electrical Impedance Spectroscopy

Abstract

Electrical methods are among the primarily studied non-invasive glucose measurement techniques; however, various factors affect the accuracy of the sensors used. Of these, the temperature is a critical factor; hence, the effects of temperature on the electrical properties of blood components are investigated in this study. Furthermore, the changes in the electrical properties of blood according to the glucose level are corrected by considering the effects of temperature on the electrical properties. An impedance sensor is developed and used to measure whole blood impedance in 10 healthy participants at various temperatures and glucose levels. Subsequently, the conductivities of the plasma and cytoplasm were extracted. Changes in the electrical properties of the blood components are then analyzed using linear regression and repeated measures ANOVA. The electrical conductivities of plasma and cytoplasm increased with increasing temperatures (plasma: 0.0397 (slope), 0.7814 (R2), cytoplasm: 0.014 (slope), 0.694 (R2)). At three values of increasing glucose levels (85.4, 158.1, and 271.8 mg/dL), the electrical conductivities of the plasma and cytoplasm decreased. These tendencies are more significant upon temperature corrections (p-values; plasma: 0.001, 0.001, cytoplasm: 0.003, 0.002). The relationships between temperature and electrical conductivity changes can thus be used for temperature corrections in blood glucose measurement.

A Highly Sensitive and Long‐Term Stable Wearable Patch for Continuous Analysis of Biomarkers in Sweat

“…Therefore, it is of high importance to integrate temperature sensors to calibrate the temperature effect. [72,73] By exploiting a serpentine-shaped pattern, the LIG temperature sensor is designed to encompass the dual-mode electrochemical sensor to sensitively detect the temperature change in the region (Figure S11, Supporting Information). The linear fit between the measured relative resistance changes and the temperature in the physiologically relevant range from 22 to 58 °C gives a sensitivity of −3.937 Ohm °C−1 (Figure 5I).…”

Microfluidic Systems for Blood and Blood Cell Characterization

“…The maximum observed rotation rate was approximately 140 • •s −1 . In recent years, the EIS method has been successfully applied for blood glucose detection [146][147][148][149][150]. Microfluidic systems for measuring the dielectric properties of blood and blood cells are shown in Figure 8.…”

A new rectangular dielectric resonator sensor for glucose measurement: Design, modeling, and experimental validation

“…18 Thermalbased techniques measure the temperature changes caused by the metabolic processes associated with glucose metabolism. 19 These methods include thermography, infrared thermometry, or heat flux measurements. Ultrasound-based techniques use sound waves to determine glucose levels.…”

“…Impedance spectroscopy, bioimpedance analysis (BIA), or skin impedance measurements are commonly employed 18 . Thermal‐based techniques measure the temperature changes caused by the metabolic processes associated with glucose metabolism 19 . These methods include thermography, infrared thermometry, or heat flux measurements.…”