Combined Biomarker Approach in the Diagnosis of Pleural Effusion Using Serum HGF, CRP, Pleural Fluid LDH/ADA, and ADA/Serum CRP Ratio: An Observational Study

Aim and background: Common diagnostic markers for pleural effusion (PE) include glucose, protein, lactate dehydrogenase (LDH), and adenosine deaminase (ADA).However, evaluating the correlation between these analytes can enhance diagnostic precision, particularly in distinguishing between different etiologies of pleural effusions.Hence, the aim of our study was to combine various serum and pleural fluid biomarkers and to evaluate their diagnostic efficacy in different types of pleural effusion.Materials and methods: Fifty-four patients who underwent thoracentesis were included in our study.Pleural fluids were assayed for complete biochemical analysis, such as ADA, LDH, total protein, albumin, glucose, and the blood samples of the same individuals were analyzed for hepatocyte growth factor (HGF) and C-reactive protein (CRP).Results: In comparison between transudative and exudative PE cases for various pleural fluids and serum biomarkers, we found a significant difference in fluid ADA (p = 0.005), fluid LDH (p = 0.003), fluid protein and albumin (p < 0.001), and pfl ADA/sCRP (p = 0.029) ratio.In comparison between tubercular pleural effusion (TPE) and malignant pleural effusion (MPE), we found a significant difference in ADA (p = 0.010), pfl ADA/ CRP (p = 0.001), and LDH/ADA (p = 0.020) ratio, and serum HGF (p = 0.04).Diagnostic accuracy of pleural fluid ADA/serum CRP marker in distinguishing between TPE and MPE has been found to have an area under the curve (AUC) of 0.68 in the ROC plot. Conclusion:The combination of multiple biomarkers in the form of ADA to CRP and LDH to ADA ratio, etc., with a newer marker such as serum HGF can improve the diagnostic efficacy in different types of pleural effusion.Clinical significance: Combining pleural fluid and serum biomarkers, especially through calculated ratios, enhances diagnostic accuracy and may aid in earlier, noninvasive differentiation of pleural effusion etiologies, guiding timely and appropriate management strategies.