This study investigates the chemical composition of blood plasma using Fourier transform infrared spectroscopy (FTIR). FTIR analysis allowed the identification of the main biochemical components, including proteins, lipids, carbohydrates and nucleic acids, by characterizing specific absorption bands. The results obtained highlight the structural and functional variations of biomolecules in plasma, providing valuable information for the assessment of physiological status and clinical diagnosis. The study demonstrates the efficiency of FTIR as a rapid, non-invasive and reproducible method for the detailed analysis of blood plasma, contributing to the development of spectroscopic tools in laboratory medicine.