A Pilot Study to Establish Incidence and Characteristics of Patients at Risk for Symptomatic Hyperammonemia Secondary to Recombinant Erwinia Asparaginase

PRIMARY OBJECTIVE: I. To determine incidence of patients who develop hyperammonemia secondary to recombinant Erwinia asparaginase. II. To characterize patients at risk for hyperammonemia secondary to recombinant Erwinia asparaginase. OUTLINE: This is an observational study. Patients undergo blood sample collection, complete surveys, and have their medical records reviewed on study.