Evaluation of prolonged aPTT values in the pediatric population.

To assess the likelihood of significant bleeding disorders in children with prolonged activated partial thromboplastin times (aPTTs), a retrospective chart review was performed. Data analyses determined that in the absence of symptoms and a negative family history, the diagnosis of a bleeding disorder was unlikely in an individual with a prolonged aPTT (negative predictive value = 80%). Conversely, a prolonged aPTT was predictive (positive predictive value = 62%) in the presence of both clinical symptoms and a documented family history. The scope of laboratory investigation in any child with a prolonged aPTT should be tempered by the clinical presentation and the associated personal and family histories.