Correlation of Cytological Findings and ADA Levels with Biochemical Findings of Pleural Fluid

This is the authors' abstract. We don't add key points for this paper.

Background: Pleural effusion is a common clinical problem with a wide range of infectious, malignant, and systemic causes.In tuberculosis-endemic countries such as India, rapid and reliable differentiation of tuberculous from nontuberculous pleural effusion is essential for timely management.Pleural fluid cytological examination and adenosine deaminase (ADA) estimation are simple, inexpensive investigations that, when interpreted together with biochemical parameters, can improve diagnostic accuracy.Objectives: To study the cytological findings and ADA levels of pleural fluid and to correlate them with the biochemical findings and final clinical diagnosis in patients presenting with pleural effusion.Methods: This prospective observational study was conducted in the Department of Pathology, Geetanjali Medical College and Hospital, Udaipur, Rajasthan, over one year (January 2017-June 2018) on 100 patients with pleural effusion.Pleural fluid obtained by thoracentesis was subjected to cytological examination and biochemical analysis, including ADA estimation, and correlated with the final etiological diagnosis.Results: Tuberculosis was the commonest cause of pleural effusion in the study population, followed by malignant, suppurative, and transudative effusions.Tuberculous pleural effusion showed marked lymphocyte predominance and significantly higher ADA activity compared with non-tuberculous effusions.At a cut-off value of 40 U/L, ADA estimation demonstrated a sensitivity and specificity exceeding 90% for the diagnosis of tuberculous pleural effusion and diagnostic specificity improved further when combined with lymphocyte predominance on cytology.Conclusion: Combined interpretation of pleural fluid cytology and ADA estimation offers a rapid, economical, and reliable approach for diagnosing tuberculous pleural effusion, and is particularly valuable in resource-limited, tuberculosis-endemic settings.