- Biomedical application of spectroscopic methods is on the rise in the last few years. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and microscopic Fourier transform infrared spectroscopy (FTIR) were applied for the analysis of human blood samples in order to detect spectral peaks which might serve as biomarkers for monitoring and identification of specific diseases. In the present study, samples of serum were obtained from healthy and patient persons suffering from diarrhea and analyzed by MALDI-TOF and advanced FTIR microscopy. The results show consistent spectral peaks in all examined serums obtained from healthy persons when tested in MALDI-TOF on the one hand, and in FTIR microscopy on the other hand. In all tested patient samples, two unique interesting peaks appeared at m / z 11,553 and 11,710 in MALDI-TOF spectra. When these patients samples were examined by FTIR microscopy, a peak at area position near 1600 cm −1 completely disappeared in FTIR spectra. These parameters could be used as a basis for developing a spectral method for the detection and identification of specific human diseases and probably other disorders.