Patent ID: 6122535
Filing Date: 2000-09-19
Classification: G01N

Abstract:
A method of determining at least the concentration of a blood component from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by a patient's tissue or transmitted through the patient's tissue, said method comprising the following steps:(a) converting the intensities of received electromagnetic signals into at least one first and one second time-dependent electric signal;(b) time-discretely transforming the first and the second time-dependent electric signal into the frequency domain for determining first and second spectral values of the first and of the second signals;(c) selecting physiologically relevant first and second spectral values by evaluating said first and second spectral values according to criteria selected in accordance with the patient's physiological parameters; and(d) calculating the concentration of the blood component making use of the selected first and second spectral values.