Updated project metadata. The aim of this study was to discover significantly changed proteins in human blood serum as a result of 6 h sleep loss at night. Eight females were reqruited. . Peripheral venous whole blood sampling was performed at 04:00, after 6 h of sleep and after 6 h of sleep deprivation (SD). Serum from each subject was depleted before protein digestion by trypsin and iTRAQ labeling. Labled peptides were analyzed by mass spectrometry.