Abstract

A device for non-invasive determination of a glucose concentration in the blood of a subject which includes a light source for producing near-infrared radiation having successive wavelengths within a range of 1300 nm to 2500 nm, a light projecting unit for projecting the near-infrared radiation on a skin of the subject, a light receiving unit for receiving a resulting radiation emitted from the inside of the skin, and a spectrum analyzing unit for making a spectrum analysis of the resulting radiation, and determining the glucose concentration according to the spectrum analysis. The light receiving unit is separated from the light projecting unit by a distance defined within a range of 0.1 mm to 2 mm to selectively sense the resulting radiation emitted from a dermis layer positioned under an epidermis layer of the skin. The glucose concentration in the blood is determined at the spectrum analyzing unit by using the spectrum analysis and a statistically-obtained correlation between glucose concentration in dermis region and glucose concentration in blood of test subjects.