Multi-step algorithm for stratifying childhood-cancer admissions. (A) Identification of a cohort of cancer-related admissions from the full KID dataset. (B) Stratification of admissions into indications for admissions. KID indicates Kids Inpatient Database; CCS indicates Clinical Classification Software. &: Includes admissions with chemotherapy as primary procedure from states with no reported procedure dates. ^: Excludes CCS diagnostic group 237 non-infectious ICD-9 codes and non-cytopenia toxicities.