IS BONE-MARROW ASPIRATION NEEDED IN ACUTE CHILDHOOD IDIOPATHIC THROMBOCYTOPENIC PURPURA TO RULE OUT LEUKEMIA

Objective: To assess the prevalence of leukemia in a series of bone ma rrow aspiration (BMA) samples collected to confirm provisional diagnos es of acute idiopathic thrombocytopenic purpura (ITP) in children. Des ign: A retrospective cohort. Setting: All BMA reports at The Hospital for Sick Children, Toronto, Ontario (a tertiary care pediatric hospita l), from January 1, 1984, to May 31, 1996, were reviewed. Patients: In cluded were BMAs performed to confirm provisional diagnoses of ITP in children (6 months to 18 years of age) with ''typical'' contemporaneou s hematologic features of ITP (platelet count, less than or equal to 5 0x10(9)/L; hemoglobin level, greater than or equal to 100 g/L [6-12 mo nths of age] or greater than or equal to 110 g/L [>1 year of age]; whi te blood cell count, greater than or equal to 5x10(9)/L [6 months to 6 years of age] or greater than or equal to 4x10(9)/L [>6 years of age] ; and neutrophil count, greater than or equal to 1.5x10(9)/L [6 months to 6 years of age] or greater than or equal to 2x10(9)/L [>6 years of age]). Children with chronic ITP, thrombocytopenia-related chronic co nditions, or leukemic blasts on peripheral smears were excluded. Main Outcome Measure: The finding of leukemia in the BMA report was chosen a priori as the primary outcome for the yield of BMA. Results: Four hu ndred eighty-four BMAs were performed to confirm provisional diagnoses of acute childhood ITP. No diagnoses of leukemia were revealed in the 332 children with typical hematologic features of ITP. The risk of mi ssing the diagnosis of leukemia in this setting is less than 195. Conc lusions: The yield of BMA for leukemia in this setting is low. Routine BMA is not necessary for children with typical acute ITP.