What additional testing, if any, should be performed for an adolescent patient with heavy menstrual bleeding and a negative von Willebrand disease evaluation?

I presume that the adolescent with heavy menstrual bleeding whose von Willebrand panel is negative has already had a CBC and baseline coagulation screen (prothrombin time, activated partial thromboplastin time, and fibrinogen or thrombin time) performed. If that is the case, I would suggest evaluation for qualitative platelet dysfunction by platelet aggregation testing. In our cohort of adolescents, prospectively followed and evaluated for qualitative platelet dysfunction, the prevalence of such...