Patent ID: 6064898
Filing Date: 2000-05-16
Classification: A61B

Abstract:
A non-invasive method for measuring the concentration of a blood component in a subject's blood, said method comprising the steps of:(a) providing at least one light source for directing light of at least one wavelength through a tissue of the subject in which light absorbance of arterial blood can be detected by measuring changes in absorbance during pulsatile flow of blood,(b) providing at least one detector for detecting the portion of the light not absorbed by the tissue of the subject;(c) measuring the absorbance of the light at the wavelength by the tissue at both the systolic and diastolic phase of the pulsatile flow;(d) determining the physical dimension of said tissue at both the systolic and diastolic phase of the pulsatile flow;(e) calculating a ratio of the change in light absorbance between the systolic and diastolic phase divided by the change in the physical dimension of said tissue between the systolic and diastolic phase;(f) determining the concentration of the blood component by comparing the ratio calculated in step (e) to a reference.