ABSTRACT
When clinicians detect a previously undiagnosed pleural eusion, a methodical evaluation can usually establish the denite or, at least, the probable cause of the eusion. is
evaluation begins with a comprehensive history and physical examination complemented by various imaging studies and serum tests to construct a probable dierential diagnosis. Establishing a denite diagnosis, however, usually requires thoracentesis and pleural uid analysis. Pleural uid analysis can (1) diagnose a specic pleural disorder, such as empyema
Introduction 153 Pleural fluid handling and ordering of tests 154 Pleural fluid appearance and odor154 Categorizing effusions as transudates
or exudates 155 Cellular assays159 Cytological analysis 161 Pleural fluid constituent assays 161
Protein 161 Lactate dehydrogenase161 Glucose 162 Pleural fluid pH162
Triglycerides and cholesterol 163 Amylase 163 Natriuretic peptides 163 Beta-2 transferrin166 Creatinine 164 Bilirubin 164 Glycine 164
Biomarkers for connective tissues diseases 164 Biomarkers for bacterial pleural infections 165 Biomarkers for tuberculous pleurisy 165 Future directions 166 References166
● Acquisition of information from a thorough history and physical examination along with routine blood and urine laboratory and chest imaging studies before thoracentesis augments the diagnostic value of pleural uid analysis.
