Abstract: The invention relates to a method for the non-invasive determination of the concentration of blood constituents, in which a radiation source (12) emits several radiation beams (14), each with a different wavelength. A first photo detector (18) receives the measurement radiation (14) of each wavelength that is reflected by a body part (16) to be examined. A second photo detector (22) receives the measurement radiation (24) of each wavelength that is transmitted by the body part (16) to be examined. The measurement radiation (14) of each wavelength that is absorbed by the body part (16) to be examined is then determined on the basis of the measurement of the reflected radiation (20) by the first radiation receiver (18) and the measurement of the transmitted radiation (24) by the second radiation receiver (22). The concentration of the different constituents is calculated from the absorption of the measurement radiation (14) that has been determined for each wavelength.

Abstract: The invention relates to a method for determining microvascular diseases wherein, first, a volume pulse development of a first blood constituent of the blood in a blood path is determined, and a volume pulse development of a second blood constituent in a blood path, being different from the first blood constituent, is determined. Thereafter, comparable reference points in the volume pulse development of the first blood constituent and in the volume pulse development of the second blood constituent are determined. Then, there is determined a temporal difference (?t) of the determined reference points in the volume pulse developments of the first blood constituent and the second blood constituent.