Pleural effusion, which is a commonly observed clinical manifestation, is associated with more than 50 recognized diseases and disorders. Measurement of this parameter may be helpful for clinicians in distinguishing between TPE and PPE. The pleural fluid LDH/ADA ratio, which can be determined from routine biochemical analysis, is highly predictive of TPE at a cut-off level of 16.20. An area under the ROC curve of 0.9663 was obtained using the LDH/ADA ratio as the indicator for TPE identification, and the sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were, respectively, 93.62%, 93.06%, 13.48, and 0.068 at a cut-off level of 16.20. A receiver operating characteristic (ROC) curve was constructed for identifying TPE. MethodsĪ retrospective study was conducted in patients with pathologically-confirmed TPE ( n = 72) and PPE ( n = 47) to compare pleural fluid LDH and ADA levels and LDH/ADA ratios between the 2 groups. In this study, we evaluated use of the pleural fluid LDH/ADA ratio as a new parameter to discriminate TPE from PPE.

Although pleural fluid lactate dehydrogenase (LDH) and adenosine deaminase (ADA) levels are often used to distinguish between tuberculous pleural effusion (TPE) and parapneumonic pleural effusion (PPE), this can be challenging as the LDH level may vary from normal to severely increased in PPE and a significantly elevated ADA is frequently measured in both conditions.

Pleural fluid