Biomarker To Evaluate Protein Profiles of Neutropenic Fever/Infection With Acute or Chronic Leukemias

You may be eligible if

• Pre-admission (ATU, ITA) or inpatient status
• absolute neutrophil count (ANC) \<= 1500/mm\^3
• Patients with acute myeloid or lymphoid leukemia who:
• * are admitted with newly diagnosed disease and have not yet received induction chemotherapy
• * are admitted with neutropenic fever after receiving post-remission chemotherapy or are admitted for post-remission chemotherapy
• Patients with chronic myeloid leukemia or a chronic lymphoid leukemia/disorder who have received chemotherapy or other disease-specific treatment in the last 30 days where the ANC of \<=1500/mm3 is considered by the treating physician to be at least possibly treatment-related
• An intravenous line or catheter (Hickman, port, portacath, or peripherally inserted central venous catheter \[PICC\] line) must be in place at the time of protocol participation/study start, but will not be inserted solely for the purposes of the study.
• Whenever possible, patients will be consented and blood monitoring will be initiated before the first dose of antibiotic, but if not possible, at no time will standard of care measures will be delayed or interrupted for the purposes of study enrollment.
• Patients must be able to understand the nature of the study and give written informed consent.