An apparatus and method for noninvasive measurement of a fluorescent analyte concentration in the blood of a patient by exciting the blood and the analyte at two wavelength ranges and measuring the emission spectrum of the fluorescent analyte when (i) the difference of emission intensities at the excitation wavelength ranges of the fluorescent analyte is greater than that of background fluorophores, and (ii) when blood absorbance at the two excitation wavelength ranges is similar. An apparatus and method for measurement of a fluorescent analyte concentration in the blood of a patient is provided.
