Embodiments of the present methods measure a concentration of a substance, such as glucose, in a body. The described embodiments change the temperature of the surface of a body from a first temperature to a second temperature, then change the temperature of the surface of the body from the second temperature back to the first temperature, and measure a first amount of infrared (&ldquo；IR&rdquo；) radiation absorbed or emitted from the surface of the body in a first wavelength band, and a second amount of IR radiation absorbed or emitted from the surface of the body in a second wavelength band at predetermined time intervals during the time period that the temperature of the surface of the body changes from the second temperature back to the first temperature. The described embodiments also measure a temperature at the surface of the body and an ambient temperature. A normalized ratio parameter is calculated from the four measurements, and the concentration of the substance in the body is determined by correlating the normalized ration parameter with the body surface temperature and the ambient temperature.グルコースなどの体内物質の濃度を測定する方法は、体表温度を第1の温度から第2の温度へと変動させる段階と、次いで体表温度を第2の温度から第1の温度へと戻るよう変動させる段階と、温度が変動する期間中に、体表が吸収または放出した第1の赤外線(「IR」)放射量を、第1の波長帯において測定する段階と、体表が吸収または放出した第2のIR放射量を、第2の波長帯において測定する段階とを含む。本方法では、体表温度および周囲温度もやはり測定する。正規化比パラメータを計算し、その正規化比パラメータを、体表温度および周囲温度と相関させることによって、体内物質の濃度を求める。
