title: Does the evaluation of coagulation factors contribute to etiological diagnosis of pleural effusions?
abstract: OBJECTIVE
  The aim of this study was to identify the participation of the coagulation system in the differential diagnosis of pleural effusions.
  
  
  BACKGROUND
  Imbalance between immunologic and metabolic factors triggers a sequence of events resulting in pleural reactions and accumulation of fluid. The coagulation system, which is fundamental for the maintenance of homeostasis, contributes to the inflammatory process responsible for pleural effusions, and participates in cellular proliferation and migration as well as in the synthesis of inflammatory mediators.
  
  
  METHODS
  We evaluated the laboratory profile of coagulation and fibrinolysis in 54 pleural fluids (15 transudates and 39 exudates).
  
  
  RESULTS
  The coagulation system acts according to the pathophysiologic mechanisms involved in the development of pleural effusions. In inflammatory effusions (exudates), there is activation of coagulation with increased levels of fragment 1+2 and thrombin-antithrombin complex in addition to reduction of fibrinogen levels due to fibrinolysis and fibrin tissue incorporation. As a consequence, there is activation of the fibrinolytic system with increased levels of fibrin degradation products, including the D-dimer. These changes are not sufficient for differentiation of different subgroups of exudates. In transudates, these events were observed to a lesser degree.
  
  
  CONCLUSIONS
  The coagulation system plays an important role in the development of pleural diseases. Coagulation tests show differences between transudates and exudates but not among exudate subgroups. Understanding the physiopathological mechanisms of pleural disorders may help to define new diagnostic and therapeutic approaches.
authors.affiliation: Pleural Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo/SP, Brazil.
authors.forename: Marcelo Alexandre Costa
authors.initials: MA
authors.lastname: Vaz
authors.forename: Francisco Suso
authors.initials: FS
authors.lastname: Vargas
authors.forename: Felipe Costa de Andrade
authors.initials: FC
authors.lastname: Marinho
authors.forename: Elbio Antonio
authors.initials: EA
authors.lastname: D'Amico
authors.forename: Tânia Rubia Flores
authors.initials: TR
authors.lastname: Rocha
authors.forename: Lisete Ribeiro
authors.initials: LR
authors.lastname: Teixeira
mesh_terms: D001777:Blood Coagulation / Q000502:physiology*; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000737:chemistry*; D005341:Fibrinolysin / Q000032:analysis*; D006801:Humans; D010996:Pleural Effusion / Q000097:blood / Q000175:diagnosis* / Q000209:etiology
chemical_list: D005341:Fibrinolysin