First, we explored visually how the differences between the urine datasets could affect the spectra. Figure depicts the average DKD and control raw spectra. It can be seen several typical bands of proteins such as the Amide A N-H stretching at 3286 cm -1 , Amide I at 1644 cm -1 and Amide II at 1538 cm -1 . In addition, the set of overlapped bands found in the 1200-1000 cm -1 region can be assigned to glycoproteins , being the glycoprotein uromodulin the most abundant protein excreted in urine of healthy individuals . In general, the DKD patients show larger intensities of protein bands than controls for both the Spanish and Australian set of data, indicative of an increase of urinary albumin excretion. Standard