Contents

Search

pleural fluid analysis

Indications: - evaluation of pleural effusion Procedure: 1) pleural fluid Gram's stain 2) pleural fluid cell count & differential 3) pleural fluid amylase 4) pleural fluid triglycerides (for chylothorax) 5) pleural fluid microbiologic stains 6) pleural fluid cultures 7) pleural fluid cytology 8) pleural fluid LDH (compared to serum LDH) 9) pleural fluid glucose 10) pleural fluid protein (compared to serum protein) 11) 10) pleural fluid adenosin deaminase (for tuberculosis) Clinical significance: - pleural fluid erythrocytes > 5000/uL - bloody appearance - associated with cancer, pulmonary infarction, asbestosis, trauma [3] - hemothorax if pleural fluid hematocrit > 50% peripheral blood hematocrit [3] - pleural fluid leukocytes > 50,000/uL - parapneumonic effusions, emphyema [3] - pleural fluid leukocytes > 10,000/uL - bacterial pneumonia, acute pancreatitis, lupus pleuritis [3] - pleural fluid leukocytes < 5000/uL - chronic exudates, tuberculous pleurisy, cancer [3] - pleural fluid lymphocytes > 80% - tuberculosis, lymphoma chronic rheumatoid pleurisy, sarcoidosis, late post CABG effusion - pleural biospy indicated in the absence of diagnosis [3] - pleural fluid lymphocytes > 10% - non-specific finding - air or blood in pleural space - parapneumonic effusion, drug-induced pleurisy, asbestosis, Churg-Strauss syndrome, lymphoma, pulmonary infarction, mycosis (coccidioidomysosis, crytococcosis, histplasmosis), parasitic infection [3] - pleural fluid eosinophils >10% - suggestive of air or blood in pleural space, - parapneumonic effusion, drug-induced pleurisy, asbestosis, Churg-Strass syndrome, lymphoma, pulmonary infarction - mycosis: coccidioidomycosis, cryptococcosis, histoplasmosis - parasitic infection [3] - pleural fluid glucose < 60 mg/dL - rheumatoid pleurisy - parapneumonic effusion, empyema - malignant effusion - tuberculous pleurisy - lupus pleuritis - esophageal rupture [3] - pleural fluid lactate dehydrogenase (LDH) - pleural fluid LDH > 0.6 x serum LDH &/or > 2/3 upper limit of normal for serum LDH is an exudate - pleural fluid protein - pleural fluid protein > 0.5 x serum protwein is an exudate - pleural fluid adenosine deaminase for tuberculosis - 60-70 U/L highly specific for Mycobacterium tuberculosis (tuberculous pleural effusion) - value < 40 U/L virtually excludes tuberculosis [3]

General

laboratory analysis

References

  1. Manual of Medical Therapeutics, 28th edition, Ewald & McKenzie (eds) Little, Brown & Co, 1995, pg 259
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 771
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015
  4. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1146
  5. Rahman NM, Mishra EK, Davies HE, Davies RJ, Lee YC. Clinically important factors influencing the diagnostic measurement of pleural fluid pH and glucose. Am J Respir Crit Care Med. 2008 Sep 1;178(5):483-90. PMID: 18556632 Free PMC Article