Evaluation of Microscopy, Adenosine Deaminase and Lactate Dehydrogenase Levels as Diagnostic Methods of Tubercular Pleural Effusion

摘要

Introduction: Pleural effusion has been associated with over 50 aetiologies, amongst which Tuberculous Pleural Effusion (TPE) is one of the most prevalent infection. TPE is highly infectious and easily transmitted. Pleural biopsy is currently, the most accepted diagnostic criteria. However, the procedure is invasive, tedious and time-consuming. Aim: To bring about a better understanding of Adenosine Deaminase (ADA), Lactate Dehydrogenase Levels (LDH), LDH: ADA ratio and microscopy as screening and diagnostic methods of TPE. Materials and Methods: The research was a hospital-based observational study which analysed 50 cases of pleural effusion. After obtaining informed consent, Pleural Fluid (PF) was collected and ADA and LDH levels were analysed. ZiehlNeelsen (ZN) staining of PF was performed and pleural biopsy was obtained. Using appropriate statistical analytical tools, Receiver Operating Characteristic (ROC) curves were prepared to find the ideal cut-off point for each diagnostic criterion. The sensitivity, specificity and Area Under Curve (AUC) for each parameter were compared. Results: In this study, 76% were males and 24% were females with a mean age of 41 years. Pleural biopsy was used as the gold standard for the positive tuberculosis case. Of the 50 cases analysed, 31 cases (62%) were reported with a positive biopsy report for TPE, while 19 (38%) presented a negative biopsy report. At a cut-off level of 26 IU/L, pleural ADA level reported sensitivity and specificity of 96.77% and 57.89%, respectively, while that of LDH was 93.55% and 68.42%, respectively at a cut-off of 326 IU/L. The LDH: ADA ratio was found to be most significant at 6.64 with a sensitivity of 93.55% and a specificity of 36.84%. The demonstration of AFB in ZN staining had 100% specificity but a mere 9.68% sensitivity. Conclusion: According to the present study, ADA had maximum sensitivity and thus, is the most suitable screening criterion for suspected cases of TPE, followed by LDH and LDH:ADA ratio, while ZN staining has maximum specificity, amongst the various parameters evaluated.