title: Initial bone marrow aspiration in childhood idiopathic thrombocytopenia: decision analysis.
abstract: OBJECTIVE
  Bone marrow aspiration (BMA) is routinely performed before starting steroid therapy in children with idiopathic thrombocytopenia, primarily to rule out leukemia.
  
  
  METHODS
  A decision tree for the initial management of a child older than age 6 months, presenting with idiopathic thrombocytopenia, without blasts on the peripheral smear was constructed. The three strategies are: 1) initial BMA in all patients; 2) initial BMA only in patients at high risk; and 3) empiric therapy for all patients without initial BMA. High-risk criteria include any of: platelet count >50 x 10(9)/L; hemoglobin <100 g/L (age younger than 12 months) or <110 g/L (age older than 12 months): white blood cell count <5 x 10(9)/L (younger than 6 years) or <4 x 10(9)/L (older than 6 years); or absolute neutrophil count <1.5 x 10(9)/L (younger than 6 years) or <2 x 10(9)/L (older than 6 years). The results are expressed as quality-adjusted life years (QALYs), a measure that estimates the overall life expectancy in years for patients receiving a particular treatment strategy, corrected for the patient's quality of life.
  
  
  RESULTS
  The base case results are: 1) BMA all = 69.649 QALYs; 2) high-risk BMA = 69.652 QALYs; and 3) empiric therapy = 69.644 QALYs. These results indicate a three-way toss-up because there is less than a 4-day quality-adjusted difference (0.01) between strategies.
  
  
  CONCLUSIONS
  This study indicates that the initial BMA does not significantly change the overall QALYs of a child presenting with thrombocytopenia and, consequently, is not mandatory in every patient before starting steroids.
authors.affiliation: Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Canada. rklaassen@cheo.on.ca
authors.forename: R J
authors.initials: RJ
authors.lastname: Klaassen
authors.forename: J J
authors.initials: JJ
authors.lastname: Doyle
authors.forename: M D
authors.initials: MD
authors.lastname: Krahn
authors.forename: V S
authors.initials: VS
authors.lastname: Blanchette
authors.forename: G
authors.initials: G
authors.lastname: Naglie
mesh_terms: D000293:Adolescent; D001707:Biopsy, Needle; D001853:Bone Marrow / Q000473:pathology; D001856:Bone Marrow Examination; D002648:Child; D002675:Child, Preschool; D003661:Decision Support Techniques; D003937:Diagnosis, Differential; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007223:Infant; D007938:Leukemia / Q000175:diagnosis* / Q000473:pathology; D008017:Life Expectancy; D008297:Male; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000175:diagnosis* / Q000473:pathology; D011788:Quality of Life; D018570:Risk Assessment; D012680:Sensitivity and Specificity