Each CSF sample was concentrated and added to a multiple affinity removal spin cartridge .The eluates were subjected to a buffer exchange and proteins were reduced using DTT and alkylated using iodoacetamide. Digestions were performed using trypsin. CSF from patients with amyotrophic lateral sclerosis (ALS) was characterized via LC-MS/MS. Biomarkers were identified to differentiate fast and slow progressors.