Non-Invasive Assessment of Blood Glucose Changes with Near Infrared Sensor

The results of the investigation of changes in optical signals of earlobe sensor at 660 and 940 nm and three-wavelengths finger sensor at 660, 850 and 940 nm during performance of 2-hour carbohydrate tolerance test are reported. Carbohydrate tolerance test (CTT) is known as the effective method of in vivo experiments to achieve a fairly wide range of glucose concentrations over a limited period of time. Measurements were carried out for 16 days in 4 non-diabetic volunteers. The results of the present study indicate that a definite optical response to the increase in blood glucose levels during the CTT, expressed after 40 min after carbohydrates uptake is observed at a wavelengths of 850 and 940 nm. The calibration coefficients were determined with the invasive glucometer and the glucose measurement errors on the Clark grid were analyzed. For the development of an optical sensor suitable for non-invasive measurement of blood glucose, further research with the use of other wavelengths in the near infrared range and technical implementation of the control of external parameters (temperature, pressure, humidity, etc.) are required.