A study on non-invasive blood glucose estimation — An approach using capacitance measurement technique

Continuous blood glucose monitoring can help and prevent hyperglycemia level in diabetic patients. In the present study we aimed to estimate the blood glucose concentration using cost effective non-invasive forearm capacitance measurement technique. This technique is based on the fact that glucose level affects the dielectric properties of blood and underlying tissue. Test procedures were performed on 10 healthy subjects with age ranging from 25 to 35 years in two phases using a designed parallel plate capacitor circuit. Forearm part act as a dielectric medium of parallel plate capacitor and 555 timer circuits is used to produce pulse waveform based on measured capacitance. In first phase, capacitance was measured after consumption of sucrose (table sugar). In second phase, capacitance was measured after consumption of artificial sweetener. A total of 25 trials were made during the whole testing process. We observed that as the blood glucose value increases, magnitude of measured capacitance value also decreases. Therefore the trend of measured capacitance obtained after sucrose consumption is similar to the trend which was already established in oral glucose tolerance (OGT) test. Hence our results are promising and show the potential of this technique in predicting in-vivo blood glucose concentration; however, further improvement of the accuracy of the device is needed by doing more trails.