It is said that every blood parameter will absorb a particular range of wavelengths. How can we decide that one particular wavelength is absorbed by that particular parameter.

I know that we will correlate the optical spectrum response and the traditional medical lab response (which is an invasive method conducted by medical lab technicians) and we conclude that there is a relation between this wavelength and parameter.

Can we directly calculate the wavelength of a particular parameter? Can we directly calculate the wavelength of glucose (C6H12O6) only with chemical bonding and without any optical experimental setup>