Patent Document ID: 6122535
Application ID: 09037947
Patent Flag: 1

Claim One:
1. 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.