Analyse du liquide pleural : orientation en première intention

Pleural fluid analysis is a determinant step in exploration of pleural effusions. In case of opaque liquid, macroscopic examination can rapidly provide clues in favour of ahaemothorax, an empyema or a lipid effusion. In case of translucent liquid, Light criteria (pleural and serumprotides and LDH) distinguishes exudates from transudates with almost 100 % specificity for the diagnosis of exudate but a sensitivity between 74 and 83 %. The albumin gradient (serum albumin -pleural albumin) may be useful in doubtful cases. Cellular count, cytology and bacteriological analysis of pleural fluid are routine analysis. Depending on the context, pleural glucose and amylose, pH, and desaminaseadenosine (ADA) can be measured.