title: Pearls and myths in pleural fluid analysis.
abstract: Virtually all patients with a newly discovered pleural effusion should undergo thoracentesis to aid in diagnosis and management. The routine pleural fluid (PF) evaluation usually includes the following: cell count and differential; tests for protein, LDH, glucose, adenosine deaminase, cytology and, if infection is a concern, pH and bacterial and mycobacterial cultures. Distinguishing transudates from exudates with Light's criteria is a pragmatic first step. If the effusion is an exudate, various PF tests have proven diagnostic utility: adenosine deaminase levels >35 IU/L usually indicate tuberculosis in lymphocyte-predominant PF; pH < 7.2 or glucose less than 60 mg/dL allow the clinician to identify complicated parapneumonic effusions; and conventional cytology may reveal malignant cells in 60% of the patients with malignant effusions. A number of optional PF tests may complement the diagnostic approach to an undiagnosed pleural effusion. For example, natriuretic peptide assays significantly improve the accuracy of a diagnosis of cardiac pleural effusion, whereas PF mesothelin levels greater than 20 nmol/L are highly suggestive of mesothelioma.
authors.affiliation: Pleural Diseases Unit, Department of Internal Medicine, Arnau de Vilanova University Hospital, Institut de Recerca Biomèdica de Lleida, Lleida, Spain. jporcelp@yahoo.es
authors.forename: José M
authors.initials: JM
authors.lastname: Porcel
mesh_terms: D000243:Adenosine Deaminase / Q000032:analysis; D005122:Exudates and Transudates / Q000737:chemistry / Q000166:cytology / Q000382:microbiology; D005947:Glucose / Q000032:analysis; D015658:HIV Infections / Q000150:complications; D006801:Humans; D007958:Leukocyte Count; D008654:Mesothelioma / Q000175:diagnosis; D045265:Natriuretic Peptides / Q000032:analysis; D009362:Neoplasm Metastasis; D019152:Paracentesis / Q000379:methods; D010996:Pleural Effusion / Q000175:diagnosis* / Q000382:microbiology / Q000473:pathology; D010997:Pleural Neoplasms / Q000175:diagnosis; D011655:Pulmonary Embolism / Q000150:complications / Q000175:diagnosis; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis
chemical_list: D045265:Natriuretic Peptides; D000243:Adenosine Deaminase; D005947:Glucose