Febrile neutropenia is a common complication in pediatric oncology patients. Standard of care requires admission of all patients for intravenous antibiotics until cultures are negative, patients are afebrile and there are signs of bone marrow recovery. This often results in prolonged hospital admissions with significant financial costs, decreased quality of life and potential secondary infections. More recent data suggests it may be possible to identify a "low risk" group that can be discharged prior to signs of bone marrow recovery. At this time, researchers have been unable to identify a model that is safe for early discharge across institutions.

1. Conduct a pilot study to determine the feasibility of using the Karius Assay to risk stratify pediatric oncology patients admitted with febrile neutropenia. This will provide preliminary data for a larger study which would randomize patients to early discharge vs. usual care.
2. Evaluate the Klaasen and SPOG clinical decision rules with and without the Karius Assay to predict patients at low risk for adverse infectious outcomes during admission. Adverse infectious outcome will be defined as: positive blood or urine culture, radiographic evidence of infection, admission to the intensive care unit or death.
3. Model potential cost savings of early discharge for patients deemed low risk for an adverse infectious outcome.

Inclusion Criteria:

1) Pediatric oncology patients, aged 1-22, treated at Lucile Packard Children's Hospital (LPCH)

Exclusion Criteria:

1. Relapsed disease
2. Acute lymphoblastic leukemia during induction
3. Acute myeloid leukemia during any phase of treatment
4. Philadelphia-chromosome positive ALL
5. Down syndrome
6. Patients who have received an allogeneic stem cell transplant.

Children being admitted for inpatient treatment with fever and neutropenia.