A Prospective Study for comparison of diagnostic utility of Gene XPERT MTB/RIF Assay, adenosine deaminase and cytology in Tuberculous Pleural Effusion

Abstract

Tubercular pleural effusion is the second most common extrapulmonary form of tuberculosis in India. It poses several health challenges in a developing country like India which has limited resources, for developing appropriate methods to diagnose. Aim: The objective of the study was to determine the role of cartridge-based nucleic acid amplification test (CBNAAT) in the diagnosis of tubercular pleural effusion (TPE) and compare it with the diagnostic utility of Adenosine Deaminase (ADA) and lymphocyte counts in pleural fluid. Methods: Total 100 patients were selected from July 2019 to December 2019. Pleural fluid was collected in sterile container. Gene/xpert, Adenosine deaminase, total leukocytes count and lymphocytes percentage were evaluated. Results: It was found that high leukocytes count and lymphocyte predominance was present in >80% of the patient. Mean ADA was 68.7 U/L ± 13.2 (SD). CBNAAT was positive in 30 patients. Acid fast bacilli stain was negative in the entire patient. Conclusion:The usefulness of Xpert MTB/RIF to diagnose pleural TB is limited by its poor sensitivity. A high ADA ≥ 40 U/L in combination with Light's criteria to define exudates, with lymphocyte predominance is sufficient evidence to diagnose tuberculous pleural effusion and initiate anti-tubercular therapy, thereby deferring the need to perform an invasive pleural biopsy.