A method of non-invasively monitoring hemoglobin concentration includes providing incident light to patient tissue at a first excitation wavelength. The method further includes monitoring a first emission response at a first emission wavelength, wherein the first emission wavelength is selected to correspond with a maximum of the emission response, and monitoring a second emission response at a second emission wavelength, wherein the second emission wavelength is selected to correspond with a minimum of the emission response. A hemoglobin concentration is calculated based on a ratio of the first emission response to the second emission response.