Clinical Utility of Pleural Fluid Protein in Differentiating Tuberculous and Malignant Pleural Effusion in a Resource-Limited Setting
DOI:
https://doi.org/10.51985/Keywords:
Diagnostic accuracy; Malignant pleural effusion; Pleural effusion; Pleural fluid proteinAbstract
Abstract
Objective: To evaluate the diagnostic performance of pleural fluid protein in differentiating tuberculous pleural effusion (TBPE) from malignant pleural effusion (MPE).
Methodology: This cross-sectional analytical study was conducted at the Department of Pulmonology, Ayub Teaching Hospital, Abbottabad, Pakistan, from October 2020 to March 2021. A total of 109 patients aged 20–75 years with pleural effusion were enrolled through consecutive non-probability sampling. Patients with end-stage renal, hepatic, or cardiac failure, terminal illness, or psychiatric disorders were excluded. Pleural biopsy with histopathological examination was used as the reference standard for diagnosing TBPE or MPE. Pleural fluid total protein was measured and categorized as <5 g/dL or =5 g/dL. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated.
Results: The mean age was 45.65 ± 15.34 years, with a near-equal gender distribution. Histopathology confirmed TBPE in 61 (56.0%) patients and MPE in 48 (44.0%). Pleural fluid protein levels =5 g/dL were observed in 46 (42.2%) patients, while 63 (57.8%) had levels <5 g/dL. Using a cutoff value of =5 g/dL, pleural fluid protein demonstrated a sensitivity of 81.97%, specificity of 72.92%, PPV of 79.37%, NPV of 76.09%, and diagnostic accuracy of 77.98% for identifying TBPE. Conclusion: Pleural fluid protein estimation shows acceptable diagnostic performance in differentiating TBPE from MPE and may serve as a useful adjunct in resource-limited settings. Although histopathology remains the gold standard, pleural
fluid protein measurement can support earlier clinical decision-making when interpreted with clinical and radiological findings
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