title: Utility of platelet function analyzer as a screening tool for the diagnosis of von Willebrand disease in adolescents with menorrhagia.
abstract: BACKGROUND
  Von Willebrand disease (VWD), and in particular, VWD type 1 and low VW factor (defined as Von Willebrand Ristocetin cofactor activity (RCoF) <30 and <50 IU/dl, respectively with normal multimers) are frequently detected in adolescents with menorrhagia and both groups benefit from similar management. Platelet function analyzer (PFA-100®) is often used as a screening test to detect VWD. We analyzed the utility of PFA-100® as a screening tool in the detection of VWD type 1 and low VW factor (VWF) in an exclusive adolescent population with menorrhagia.
  
  
  METHODS
  The study population consisted of adolescents with menorrhagia who had simultaneously drawn blood samples for VWD and PFA-100®. Abnormal PFA-100® was defined as values >183 seconds for collagen/epinephrine and/or >126 seconds for collagen/ADP.
  
  
  RESULTS
  Of a total of 235 patients tested, 23 patients had RCoF <50 IU/dl and normal multimer patterns. Statistical analysis of the utility of PFA-100® in detecting RCoF <50 IU/dl with normal multimers yielded sensitivity, specificity, positive predictive, and negative predictive values of 52%, 89%, 34%, and 95%, respectively.
  
  
  CONCLUSIONS
  Based on our results, PFA-100® was not sufficiently sensitive to detect RCoF values <50 IU/dl with normal multimer patterns in teen-aged women with menorrhagia. We conclude that in the setting of adolescent menorrhagia, PFA-100® does not have utility as an initial screening test for the diagnosis of VWD and in particular, low VWF and that clinicians need to be aware of this limitation of PFA-100® while evaluating adolescents with menorrhagia.
authors: Section of Hematology and Oncology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.
authors: Swati
authors: S
authors: Naik
authors: Jun
authors: J
authors: Teruya
authors: Jennifer E
authors: JE
authors: Dietrich
authors: Purvi
authors: P
authors: Jariwala
authors: Esther
authors: E
authors: Soundar
authors: Lakshmi
authors: L
authors: Venkateswaran
mesh_terms: D000293:Adolescent; D001792:Blood Platelets / Q000473:pathology*; D005260:Female; D006801:Humans; D008595:Menorrhagia / Q000209:etiology*; D010979:Platelet Function Tests / Q000379:methods*; D012680:Sensitivity and Specificity; D014842:von Willebrand Diseases / Q000150:complications / Q000175:diagnosis*