On presentation to the ED, all patients will have a CBC with differential, blood culture from the central line and procalcitonin levels drawn. All will receive empiric antibiotics initiated with either Ceftriaxone (if the patients is clinically stable and non-neutropenic defined as an Absolute Neutrophil Count (ANC)>1500 cells/microliter) or with Cefepime and Gentamicin in the neutropenic or ill appearing patient.