A comparative analysis of the biochemical parameters used to distinguish between pleural exudates and transudates.

OBJECTIVE

The aim of the present study was to compare the various parameters used to identify exudates.

METHODOLOGY

The study included 255 patients with pleural effusions. According to aetiological diagnosis, 105 pleural effusions were labelled as transudates and 150 were labelled as exudates.

RESULTS

Using the criteria of Light et al., 94.5% of the effusions were correctly classified, yielding a sensitivity and specificity of 99.3% and 87.6%, respectively. Use of the pleural fluid/serum bilirubin ratio produced results of 92.9%, 90.7%, and 96.2%, respectively. Using pleural fluid cholesterol level yielded results of 95.7%, 95.3%, and 96.2%, respectively. When the combination of pleural fluid cholesterol level and lactate dehydrogenase (LDH) level was used, the specificity and accuracy were found to be higher than that using the criteria of Light et al. We found that there was no significant difference among the parameters with respect to accuracy.

CONCLUSION

When the accuracy and cost are considered, differentiation of pleural exudates and transudates can be achieved only by pleural fluid cholesterol level or LDH level; and when two parameters were used together, the accuracy and specificity were higher than that using the criteria of Light et al.