Contenti J, et al. - This retrospective cohort study was performed to evaluate the clinical situations leading emergency physicians to take a blood lactate sample, the prevalence of hyperlactatemia and its impact on short-term adverse outcome. Observations suggested that in Emergency Departments, blood lactate testing has become routine. A large proportion of patients demonstrate abnormal blood lactate levels in the ED mostly because of infection and seizures. However, the prognostic value of blood lactate seems to be different from one diagnostic category to the other.