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 evaluati...