Sepsis remains a leading cause of morbidity and mortality in neonates worldwide. There is also clinically a low threshold for suspicion of infection in neonates, in particular as presentation varies greatly from very subtle to catastrophic collapse. The lack of reliably sensitive tests and the potential life-threatening consequences of delayed treatment of infection results in the widespread use of empirical antibiotics exposing many infants without infection to broad-spectrum antibiotics. The present invention provides a series of patient-invariant biomarkers for screening neonates and other subjects for infection that predicts bacterial infection with high accuracy; and is further shown to have predictive value in identifying infection in suspected cases with blood-culture negative tests.