A novel analytical procedure was developed for the rapid determination of disease biomarkers of maple syrup urine disease (MSUD), L-valine, L-leucine, L-isoleucine, and L-phenylalanine in dried blood spots. Amino acids extracted from neonatal dried blood spots were rapidly derivatized with bis-(trimethylsilyl)trifluoroacetamide (BSTFA) and then analyzed by gas chromatography-mass spectrometry (GC-MS). Derivatization conditions and the method validation were studied: optimal derivatization conditions were acetonitrile as reaction solvent, a temperature of 100 degrees C, and a reaction time of 30 min. The proposed method provided a detection limit lower than 2.0 microM, recovery between 92% and 106%, and relative standard deviation less than 8.0%. The method was further tested in screening for neonatal MSUD by determination of L-valine, L-leucine, L-isoleucine, and L-phenylalanine in blood samples. The experimental results show that GC-MS following BSTFA derivatization is a rapid, simple, and sensitive method for the determination of amino acid disease biomarkers in blood samples, and is a potential tool for fast screening of MSUD.