Figure 1:

A total of 20,522 patients with 2 or more SIRS criteria were identified. Patients younger than 18 years of age (3,878) and subsequent sepsis episodes during hospitalization (1,500) were excluded, resulting in 15,144 patients. Then, patents were further excluded if they had grown positive cultures from samples taken 0 to 48 hours prior to presentation (2,888) or beyond 24 hours after presentation (1,863) resulting in 10,393 patients of whom 9,288 were culture negative and 1,105 were culture positive. SIRS = Systemic Inflammatory Response Syndrome; Culture negative = patients who had samples taken during the first 24 hours of presentation that did not grow a pathogen; Culture positive = patients who had samples taken during the first 24 hours of presentation that did grow a pathogen.