title: [Contribution of pleural fluid analysis to the diagnosis of pleural effusion].
abstract: Analysis of pleural fluid can have, on its own, a high diagnostic value. In addition to thoracocentesis, a diagnostic hypothesis based on medical history, physical examination, blood analysis and imaging tests, the diagnostic effectiveness will significantly increase in order to establish a definite or high probable diagnosis in a substantial number of patients. Differentiating transudates from exudates by the classical Light's criteria helps knowing the pathogenic mechanism resulting in pleural effusion, and it is also useful for differential diagnosis purposes. An increased N-terminal pro-brain natriuretic peptide, both in the fluid and in blood, in a due clinical context, is highly suggestive of heart failure. The presence of an increased inflammatory marker, such as C-reactive protein, together with the presence of over 50% of neutrophils is highly suggestive of parapneumonic pleural effusion. If, in these cases, the pH is<7.20, then the likelihood of complicated pleural effusion is high. There remains to be demonstrated the usefulness of other markers to differentiate complicated from uncomplicated effusions. An adenosine deaminase > 45 U/L and>50% lymphocytes is suggestive of tuberculosis. If a malignant effusion is suspected but the cytological result is negative, increased concentrations of some markers in the pleural fluid can yield high specificity values. Increased levels of mesothelin and fibruline-3 are suggestive of mesothelioma. Immunohistochemical studies can be useful to differentiate reactive mesothelial cells, mesothelioma and metastatic adenocarcinoma. An inadequate use of the information provided by the analysis of pleural fluid would results in a high rate of undiagnosed effusions, which is unacceptable in current clinical practice.
authors.affiliation: Servicio de Neumología, Complejo Hospitalario Clínico-Universitario de Santiago Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: Lucía
authors.initials: L
authors.lastname: Ferreiro
authors.affiliation: Servicio de Neumología, Complejo Hospitalario Clínico-Universitario de Santiago Santiago de Compostela, Santiago de Compostela, A Coruña, España.
authors.forename: María Elena
authors.initials: ME
authors.lastname: Toubes
authors.affiliation: Servicio de Neumología, Complejo Hospitalario Clínico-Universitario de Santiago Santiago de Compostela, Santiago de Compostela, A Coruña, España; Grupo Interdisciplinar de Investigación en Neumología, Instituto de Investigaciones Sanitarias de Santiago (IDIS), Santiago de Compostela, A Coruña, España. Electronic address: luis.valdes.cuadrado@sergas.es.
authors.forename: Luis
authors.initials: L
authors.lastname: Valdés
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000556:secondary; D000243:Adenosine Deaminase / Q000032:analysis; D001327:Autoimmune Diseases / Q000150:complications / Q000378:metabolism; D015415:Biomarkers; D001826:Body Fluids / Q000737:chemistry* / Q000166:cytology; D002097:C-Reactive Protein / Q000032:analysis; D003937:Diagnosis, Differential; D004066:Digestive System Diseases / Q000150:complications / Q000378:metabolism; D016724:Empyema, Pleural / Q000150:complications / Q000378:metabolism; D005947:Glucose / Q000032:analysis; D006333:Heart Failure / Q000097:blood / Q000150:complications; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018836:Inflammation Mediators / Q000032:analysis; D007958:Leukocyte Count; D008055:Lipids / Q000032:analysis; D008214:Lymphocytes / Q000201:enzymology; D008654:Mesothelioma / Q000737:chemistry / Q000556:secondary; D045265:Natriuretic Peptides / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis; D010996:Pleural Effusion / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000378:metabolism; D011014:Pneumonia / Q000150:complications / Q000378:metabolism; D000069258:Thoracentesis; D014376:Tuberculosis / Q000150:complications / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators; D008055:Lipids; D045265:Natriuretic Peptides; D009363:Neoplasm Proteins; D002097:C-Reactive Protein; C548482:ADA protein, human; D000243:Adenosine Deaminase; D005947:Glucose
keywords: Analysis of pleural fluid; Análisis del líquido pleural; Derrame pleural; Derrame pleural neoplásico; Derrame pleural paraneumónico; Derrame pleural tuberculoso; Diagnosis of pleural effusion; Diagnóstico del derrame pleural; Malignant pleural effusion; Parapneumonic pleural effusion; Pleural effusion; Tuberculous pleural effusion