Non-Invasive Blood Glucose Measurement Using Near Infra-Red Spectroscopy

The primary focus in designing medical diagnosis and instrumentation devices apart from improving accuracy is to enhance their ease of usage and making them more accessible and inexpensive. Blood sugar level is a significant parameter to consider during any medical check-up. High or inconsistent levels of glucose in blood is an alarming sign and may imply the presence of diabetes. Hence, regular monitoring the concentration of sugar in blood thus becomes imperative. Conventionally this is done using devices which invade the skin barrier and require using needles and strips. The invasive process not only constitutes health hazards but also requires spending on replacements of the strips, the cost of which is not negligible. Using infra-red spectroscopy a quantitative correlation between the concentration of glucose and of near IR radiation can be established. The work presented here introduces a device capable of acquiring a measurement in a non-invasive manner. The device which is to be worn on a fingertip calculates the concentration of glucose present by first measuring the amount of radiation passing through the blood vessels in the subject's finger and then using a calibration curve to find a value in mmol/L. To compensate for variations in finger depth, the distance between the IR emitter and receiver was measured using an IR sensor and the IR absorbance readings were normalized to eliminate any aberrant effect this could potentially pose.