title: C-reactive protein in lymphocytic pleural effusions: a diagnostic aid in tuberculous pleuritis.
abstract: BACKGROUND
  C-reactive protein (CRP) pleural fluid levels have been found to be higher in tuberculosis and parapneumonic effusions than in other causes of pleural effusion.
  
  
  OBJECTIVE
  The aim of this study was to analyze whether CRP (a simple and inexpensive test) may be a diagnostic aid for tuberculosis in lymphocytic pleural effusions.
  
  
  METHODS
  One hundred and forty-four patients with a lymphocytic pleural effusion (more than 50% lymphocytes in the differential white blood cell count) were included. The patients were 93 men (65%) and 51 women (35%), aged 64 +/- 18 years (mean +/- SD). The diagnoses were as follows: tuberculosis, 20; pleural effusion associated with malignancy, 69; transudates, 38; other benign exudates, 17.
  
  
  RESULTS
  The CRP pleural fluid level was higher in tuberculous pleuritis (54 +/- 24 mg/l) than in lymphocytic effusions of other origin (21 +/- 16 mg/l; p < 0.001). High CRP levels (>or=50 mg/l) have a high specificity for tuberculosis (95%), and low levels (<30 mg/l) have a high sensitivity (95%) for excluding disease.
  
  
  CONCLUSIONS
  CRP pleural fluid level determination is useful in the diagnostic workup of lymphocytic pleural effusions. High CRP levels are very suggestive of tuberculous pleuritis, and low CRP levels make this diagnosis unlikely.
authors.affiliation: Section of Pneumology, Hospital General Universitario, Elche, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia-Pachon
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Soler
authors.forename: Isabel
authors.initials: I
authors.lastname: Padilla-Navas
authors.forename: Victor
authors.initials: V
authors.lastname: Romero
authors.forename: Conrado
authors.initials: C
authors.lastname: Shum
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D005122:Exudates and Transudates / Q000378:metabolism; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000209:etiology / Q000378:metabolism*; D011237:Predictive Value of Tests; D014396:Tuberculosis, Pleural / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism*
chemical_list: D002097:C-Reactive Protein