ABSTRACT

Background: Rapid diagnostics of exudative pleural effusion should be able to rule out tuberculosis (TB) as the causative agent. Cancer ratio, a ratio between serum lactate dehydrogenase (LDH) and pleural fluid adenosine deaminase (ADA), of >20 is predictive for malignant pleural effusion (MPE). This study aimed to observe the diagnostic values and to determine the diagnostic cut-off point of cancer ratio for MPE in a country with a high TB burden such as Indonesia.

Methods: This prospective cross-sectional study involved 65 subjects with exudative pleural effusion suspected of malignancy and treated at Persahabatan Hospital Jakarta, Indonesia.

Results: Cancer ratio >20 had a sensitivity of 61.82%, specificity of 80%, positive predictive value (PPV) of 94.44% and negative predictive value (NPV) of 27.59%. The cancer ratio cut-off points of >26 showed sensitivity and specificity of 0.43 (95%CI 0.31-0.55) and 0.9 (95%CI 0.82-0.97) respectively. The area under the curve (AUC) of 0.76 indicated good accuracy. The positive likelihood ratio (PLR) was found to be 4.36 (95%CI 3.43-5.29), while the negative likelihood ratio (NLR) at this cut-off point was 0.22 (95%CI 0.13-0.33). Moreover, the PPV and NPV were found to be 0.96 (95%CI 0.91-1) and 0.22 (95% CI 0.12-0.32) respectively.

Conclusion: Based on its high specificity, PPV and PLR, cancer ratio cut-off point of >26 was found highly predictive of malignancy in patients with exudative pleural effusion in a country with high TB burden.