Last reviewed: February 2018
Last updated: November  2017



History and exam

Key diagnostic factors

  • presence of risk factors
  • dyspnoea
  • dullness to percussion

Other diagnostic factors

  • pleuritic chest pain
  • cough
  • quieter breath sounds
  • decreased or absent tactile fremitus

Risk factors

  • CHF
  • pneumonia
  • malignancy
  • pulmonary embolism
  • recent CABG surgery
  • recent MI
  • occupational lung disease
  • rheumatoid arthritis
  • SLE
  • renal failure
  • drug induced
  • chylothorax

Diagnostic investigations

1st investigations to order

  • posteroanterior (PA) and lateral CXR
  • pleural ultrasound
  • LDH and protein in pleural fluid and serum
  • RBC count in pleural fluid
  • WBC count and differential of pleural fluid
  • cytology of pleural fluid
  • culture of pleural fluid
  • pH of pleural fluid
  • glucose in pleural fluid
  • pleural fluid cholesterol level
  • protein gradient
  • FBC
  • CRP
  • blood culture
  • sputum Gram stain and culture
  • NT-proBNP in pleural fluid
Full details

Investigations to consider

  • thoracic CT scan
  • thoracic MRI
  • helical CT scan
  • amylase in pleural fluid
  • adenosine deaminase (ADA) level in pleural fluid
  • lipid analysis of pleural fluid
  • thoracoscopy
  • bronchoscopy
  • pleural biopsy
Full details

Emerging tests

  • tumour markers in pleural fluid
  • interferon-gamma in pleural fluid and real-time PCR of pleural fluid
  • soluble triggering factor expressed on myeloid cells
Full details

Treatment algorithm


Authors VIEW ALL

Consultant Respiratory Physician

Chelsea and Westminster Hospital NHS Foundation Trust




OO declares that he has no competing interests.

Consultant Respiratory Physician and Pleural Lead

Imperial College Healthcare NHS Trust




CR declares that she has no competing interests.

Dr Orhan Orhan and Dr Clare Ross would like to gratefully acknowledge Dr Philip W. Ind, Dr Anob M. Chakrabarti, Dr Richard Light, Dr Amber Degryse, Dr Rachel J. Davies, and Dr Peter M. George, the previous contributors to this monograph. RL has received speaking fees provided by Cardinal Health; owned stock in Denver Biomaterials until it was purchased by Cardinal Health; received fees for consulting from Denver Biomaterials; and is an author of a number of references cited in this monograph. PWI, AMC, AD, RJD, and PMG declare that they have no competing interests.

Peer reviewers VIEW ALL

Consultant Chest Physician and Senior Lecturer

Oxford Centre for Respiratory Medicine and University of Oxford Churchill Hospital




YCGL declares that he has no competing interests.

Pleural Research Registrar

North Bristol Lung Centre

Southmead Hospital

Westbury on Trym




CH declares that she has no competing interests.

Professor of Medicine and Director

Division of Pulmonary/Critical Care/Allergy/Sleep Medicine

Medical University of South Carolina




SS declares that he has no competing interests.

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