JMIR Publications

ABSTRACT

Background:

Differentiating between tuberculosis and malignancy as the cause of an exudative lymphocyte predominant pleural effusion is difficult due to similarities in the cellular and biochemical characteristics of the pleural fluid in both conditions. Microbiological tests in tubercular pleural effusions have a poor diagnostic yield, and the long turnaround time for results prevents an early diagnosis. The diagnosis of malignant pleural effusion is hampered by a variable yield of pleural fluid cytology and closed pleural biopsy and the fact that thoracoscopy may not be readily available or feasible in each patient. This study explores the utility of the serum LDH/pleural ADA ratio (i.e., 'Cancer Ratio') in discriminating between tuberculous and malignant pleural effusion.

Objective:

To evaluate the ‘cancer ratio’ (i.e., serum LDH/pleural ADA ratio) as a test to differentiate tubercular and malignant etiology in patients with an exudative lymphocytic pleural effusion.

Methods:

This hospital-based prospective observational study will include patients admitted with pleural effusion whose pleural fluid reports indicate a lymphocyte-predominant exudate. The ability of the cancer ratio (CR) to discriminate between tuberculous and malignant pleural effusion will be evaluated as a primary objective of this study. The performance of CR and pleural fluid CEA in the diagnosis of malignant pleural effusion will be compared using the receiver operating characteristics (ROC) and the area under the curve (AUC) for both tests as a secondary objective. The association between a positive CR and histologic type of lung cancer will be analyzed as well.

Results:

This study is being submitted after data collection and before analysis of data collected. The Study investigator will calculate the sensitivity, specificity, negative predictive value, positive predictive value, and diagnostic accuracy rate from the derived results to evaluate the diagnostic accuracy of CR in MPE. The diagnostic performance of CR and pleural fluid CEA as predictors for MPE will be compared using the receiver operating characteristics (ROC) and the area under the ROC (AUC), taking cut-off values of > 20 and 2.4ng/ml, respectively.

Conclusions:

The results of this study will provide an objective basis for the use of CR in differentiating between tuberculosis and malignancy as the cause of an exudative lymphocyte predominant pleural effusion. Clinical Trial: Applied for registration with The Clinical Trials Registry – India (CTRI).