title: Failure of the Platelet Function Assay (PFA)-100 to detect antiplatelet agents.
abstract: BACKGROUND
  Antiplatelet therapy is a complicating factor in patients with traumatic brain injuries (TBI), as well as those with hemorrhagic cerebrovascular accidents (CVAs). Platelet Function Assay (PFA)-100 is a coagulation device that can detect platelet dysfunction caused by aspirin and adenosine diphosphate inhibition. Our retrospective study reviewed the effectiveness of PFA-100 in detecting platelet dysfunction caused by aspirin and clopidogrel and determined its clinical importance.
  
  
  METHODS
  All patients with PFA-100 tests from January 2013 to February 2014 were collected. Diagnoses indicative of a TBI or CVA were chosen for analysis. Patients with a normal PFA-100 indicating no platelet dysfunction but with documented aspirin and/or clopidogrel use were selected. An extensive chart review was performed to determine the relevance to their clinical care.
  
  
  RESULTS
  A total of 475 patients were evaluated with a PFA-100 from January 2013 to February 2014. PFA-100 detected platelet dysfunction as the result of pre-injury use of antiplatelet agents in TBI and CVA patients with a sensitivity of only 48.6% and a specificity of 74.8%. Had these antiplatelet medications been known during initial workup, these patients would have had a change in management that may have impacted their outcomes.
  
  
  CONCLUSIONS
  Despite its common usage, the PFA-100 is an unreliable tool to assist in the management of TBI and CVA patients. Additional investigation into alternative methods for detecting platelet dysfunction is warranted.
authors: University of Missouri-Columbia, Columbia, MO. Electronic address: bartelsan@health.missouri.edu.
authors: Ashley
authors: A
authors: Bartels
authors: University of Missouri-Columbia, Columbia, MO.
authors: Yaw
authors: Y
authors: Sarpong
authors: University of Missouri-Columbia, Columbia, MO.
authors: Jared
authors: J
authors: Coberly
authors: University of Missouri-Columbia, Columbia, MO.
authors: Natalie
authors: N
authors: Hughes
authors: University of Missouri-Columbia, Columbia, MO.
authors: Jeffrey
authors: J
authors: Litt
authors: University of Missouri-Columbia, Columbia, MO.
authors: Jacob
authors: J
authors: Quick
authors: University of Missouri-Columbia, Columbia, MO.
authors: James
authors: J
authors: Kessel
authors: University of Missouri-Columbia, Columbia, MO.
authors: Christopher
authors: C
authors: Nelson
authors: University of Missouri-Columbia, Columbia, MO.
authors: Jeffery
authors: J
authors: Coughenour
authors: University of Missouri-Columbia, Columbia, MO.
authors: Stephen L
authors: SL
authors: Barnes
authors: University of Missouri-Columbia, Columbia, MO.
authors: N Scott
authors: NS
authors: Litofsky
authors: University of Missouri-Columbia, Columbia, MO.
authors: Richard D
authors: RD
authors: Hammer
authors: University of Missouri-Columbia, Columbia, MO.
authors: Salman
authors: S
authors: Ahmad
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000009:adverse effects*; D001791:Blood Platelet Disorders / Q000139:chemically induced / Q000150:complications / Q000175:diagnosis*; D001930:Brain Injuries / Q000150:complications* / Q000628:therapy; D000077144:Clopidogrel; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects*; D010979:Platelet Function Tests; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications* / Q000628:therapy; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin