The invention provides a method for non-invasively determining haemoglobin and
oxygen concentrations in the blood, and relates to the field of analysis of the
chemical composition of materials and canbe used in diagnostic
medical equipment for non-invasively determining haemoglobin and
oxygen concentrations in the blood. The method comprises exposing a
biological tissue to an
optical radiation infirst, second and third
wavelength ranges successively, which comprise the values of 700 nm, 880 nm and 960 nm respectively; receiving the reflected
optical radiation; converting the latter into an
electric signal; determining the haemoglobin concentration on the basis of the sum of the electrical signals obtained during
exposure to the
optical radiation in the first and second
wavelength ranges,which sum is reduced by a value determined by means of the
electric signal obtained during
exposure to the optical
radiation in the third range; and determining the
oxygen concentration on the basisof the difference between the electrical signals obtained during
exposure to the optical
radiation in the first and second
wavelength ranges, which difference is reduced by a value determined by meansof the
electric signal obtained during exposure to the optical
radiation in the third range. The invention makes it possible, when determining haemoglobin and oxygen concentrations, to reduce inaccuracies caused by the presence of water in the
biological tissue undergoing examination.