You will have blood drawn (less than 1 teaspoon each) for PK testing at different time points throughout this study. PK tests measure the level of the study drug in the blood at different times. You will have a total of 14 samples drawn. Your blood will be drawn on Day 1 before your dose of rasburicase and then at 30 minutes and at 4, 8, 24, 48, 72, 96, 96.5,100,104,120 (Day 6),168 (Day 8), and 336 (Day 15) hours after your dose of the study drug.