title: The role of the Platelet Function Analyzer (PFA)-100 and platelet aggregometry in the differentiation of essential thrombocythemia from reactive thrombocytosis.
abstract: BACKGROUND
  The most crucial component of all diagnostic criteria for essential thrombocythemia (ET) has been the exclusion of reactive thrombocytosis (RT). Our aim was to evaluate the diagnostic performance of the PFA-100 collagen-epinephrine (CEPI) cartridge test and epinephrine-induced aggregometry individually, but mainly combined, in the differentiation of ET from RT.
  
  
  METHODS
  26 patients with ET and 25 with RT were studied. Platelet function was analyzed by the PFA-100 and by light transmission aggregometry with epinephrine and ADP. The JAK2 mutational status was identified and hematological parameters, plasma von Willebrand factor antigen and activity levels were also assessed.
  
  
  RESULTS
  The sensitivity (Se), specificity (Sp), positive predictive value (PPV), and the negative predictive value (NPV) of PFA-100 CEPI vs epinephrine-induced aggregometry in the differentiation of ET from RT were estimated as follows: Se (%): 78.9 vs 84.6, Sp (%): 92.0 vs 96.0, PPV (%): 88.2 vs 95.7, NPV (%): 85.2 vs 85.7, respectively. When both of these methods were combined, a lower sensitivity of 68.4%, but a specificity of 100% was attained. The PPV observed with this double abnormal combination was 100% and the NPV 80.6%. Lastly, when we assessed the abnormality for either CEPI CT or epinephrine-induced aggregometry, the sensitivity was 100%, the specificity 88.0%, PPV 86.4% and NPV 100%. Thus, an abnormal combination was strongly suggestive of ET, while normal results with both methods excluded ET.
  
  
  CONCLUSIONS
  If our results are replicated by further studies, these two methods could be used very effectively as adjunct markers in the differentiation between ET and RT.
authors: Laboratory of Haematology and Blood Bank Unit, Attikon General Hospital, School of Medicine, University of Athens, Athens, Greece. atsantes@yahoo.com
authors: Argirios E
authors: AE
authors: Tsantes
authors: Aikaterini
authors: A
authors: Dimoula
authors: Stefanos
authors: S
authors: Bonovas
authors: Georgios
authors: G
authors: Mantzios
authors: Panagiotis
authors: P
authors: Tsirigotis
authors: Katerina
authors: K
authors: Zoi
authors: Eleni
authors: E
authors: Kalamara
authors: Aikaterini
authors: A
authors: Kardoulaki
authors: Nikolaos
authors: N
authors: Sitaras
authors: Anthi
authors: A
authors: Travlou
authors: John
authors: J
authors: Dervenoulas
authors: George
authors: G
authors: Vaiopoulos
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology; D003937:Diagnosis, Differential; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D010976:Platelet Count / Q000295:instrumentation; D010979:Platelet Function Tests / Q000295:instrumentation; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013920:Thrombocythemia, Essential / Q000175:diagnosis*; D013922:Thrombocytosis / Q000175:diagnosis*
chemical_list: D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine