Abstract: The present invention relates to a method for detecting blood characteristics including hemoglobin in a fluid medium using both transmission and reflection of a light beam which forms a quotient.

Abstract: The present invention provides a non-invasive method for measuring blood circulation in tissue comprising the steps a) directing a first light beam and a second light beam coming from two different light sources with approximately the same wavelength against the tissue; b) detecting the intensity of the light of the first and second light beam, respectively, reflected from the tissue by using a detector appearing between said light sources; c) calculating a quotient of the detected intensity and a pre-determined zero-level intensity or a quotient of the detected intensity and a reference intensity; d) analyzing the quotient to determine the blood circulation; e) optionally, registering the quotient; and/or f) optionally, visualizing the quotient. The present invention also relates to and a computer program as well as an apparatus for performing said method.