Abstract: Currently, there are no continuous, non-invasive blood glucose monitors. With over 366 million people worldwide expected to be diagnosed as diabetic by 2030, an alternative to the current invasive methods is critical. This paper investigates the use of a discrete spectometric, NIR reflectance glucometer to detect a change in glucose concentration in solution. At each wavelength, an LED is used to emit light, and a reverse-biased LED detects light using wavelengths 660 nm, 850 nm, 940 nm, 1450 nm, 1550 nm, 1650 nm. The discharge time of a reverse-biased LED is proportional to the temporal integral of the detected light intensity. The sensor’s response to changing glucose concentration was tested in both water and porcine blood. Glucose concentration was increased by 0.5 mmol l−1 and compared with a finger stick glucometer. Each wavelength exhibited an expected change in adsorption given only an increase in glucose concentration. The inverted exponential increase in absorption is explained by Beer Lambert’s law. Wavelengths 660 nm, 850 nm and 1450 nm showed minimal change to absorption, while 940 nm, 1550 nm and 1650 nm showed considerable change in absorption. The 1550 nm LED gave the greatest increase in absorption with a 7% rise over 4.3 mmol l−1 to 20.6 mmol l−1. Ratios of absorption responses (R1550/1650, R1550/1450 and R940/850) each gave proportional increases in absorption with increasing glucose concentrations.