Role of CRP as a marker for discrimination of exudative and transudative pleural effusion

Cancer Research UK / Wikimedia Commons
Submitted: August 27, 2021
Accepted: March 10, 2022
Published: March 14, 2022
Abstract Views: 1272
PDF: 420
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Differentiation between exudative and transudative pleural effusion is sometime problematic. This study aimed to evaluate the diagnostic value of C-reactive protein (CRP) in differentiation of exudative and transudative pleural effusion. This is an analytical epidemiologic cross-sectional study that evaluates the role of CRP in differentiating transudative and exudative pleural effusion. Patients were divided into two groups of exudates and transudates, based on Light’s criteria. The pleural effusion CRP levels were compared between the two groups. SPSS software version 16 was used for statistical analysis. The significance level was considered p<0.05. A total of 169 patients with pleural effusion enrolled in the study. Based on Light's criteria, 108 patients (63.9%) had exudative pleural effusion and 61 (36.1%) had transudative pleural effusion. The level of CRP in the pleural fluid of patients in the exudative and transudative groups was 13.3±37.1 and 3.5±4.3mg/dl, respectively (p=0.008). The 3.31 mg/dl cut-off point of CRP level of pleural effusion had the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 96.3%, 72.1%, 86% and 91.7% respectively.  The results obtained in our study shows that the level of CRP in the effusion fluid can be helpful in differentiating exudative from transudative pleural effusions.



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Porcel JM, Light RW. Pleural effusions. Dis Mon 2013;59:29-57. DOI:
Rezaeetalab F, Parizadeh SMR, Esmaeely H, et al. Tumor necrosis factor alpha and high sensitivity C-reactive protein in diagnosis of exudative pleural effusion. J Res Med Sci 2011;16:1405-9.
Kiropoulos TS, Kostikas K, Oikonomidi S, et al. Acute phase markers for the differentiation of infectious and malignant pleural effusions. Respir Med 2007;101:910-8. DOI:
Turay ÜY, Yildirim Z, Türköz Y, et al. Use of pleural fluid C-reactive protein in diagnosis of pleural effusions. Respir Med 2000;94:432-5. DOI:
Vidriales JC, Antequera CA. Use of pleural fluid C-reactive protein in laboratory diagnosis of pleural effusions. Eur J Med 1992;1:201-7.
Garcia-Pachon E, Llorca I. Diagnostic value of C-reactive protein in exudative pleural effusions. Eur J Intern Med 2002;13:246-9. DOI:
Aleman C, Alegre J, Monasterio J, et al. Association between inflammatory mediators and the fibrinolysis system in infectious pleural effusions. Clin Sci 2003;105:601-7. DOI:
Marel M, Štastny B, Melinová L, et al. Diagnosis of pleural effusions: experience with clinical studies, 1986 to 1990. Chest 1995;107:1598-603. DOI:
Gewurz H, Mold C, Siegel J, Fiedel B. C-reactive protein and the acute phase response. Adv Intern Med 1982;27:345-72. DOI:
Okamura J, Miyagi J, Terada K, Hokama Y. Potential clinical applications of C‐reactive protein. J Clin Lab Anal 1990;4:231-5. DOI:
Izhakian S, Wasser WG, Fox BD, et al. The diagnostic value of the pleural fluid C-reactive protein in parapneumonic effusions. Dis Markers 2016;2016:7539780. DOI:
Light RW, Macgregor MI, Luchsinger PC, Ball Jr WC. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Int Med 1972;77:507-13. DOI:
Porcel JM, Bielsa S, Esquerda A, et al. Pleural fluid C-reactive protein contributes to the diagnosis and assessment of severity of parapneumonic effusions. Eur J Intern Med 2012;23:447-50. DOI:
Daniil ZD, Zintzaras E, Kiropoulos T, et al. Discrimination of exudative pleural effusions based on multiple biological parameters. Eur Respir J 2007;30:957-64. DOI:
Kapisyzi P, Argjiri D, Byrazeri G, et al. Use of pleural fluid c-reactive protein level as a diagnostic marker for pleural effusions. Chest 2009;136:30S. DOI:
Gabhale D, Taparia P, Yadav D, Agnihotri S. Usefulness of pleural fluid CRP level in differential diagnosis of exudative pleural effusion - a pilot study. Int J Clin Biochem Res 2015;2:97-109.
Skouras V, Boultadakis E, Nikoulis D, et al. Prognostic value of C‐reactive protein in parapneumonic effusions. Respirology 2012;17:308-14. DOI:

How to Cite

Rismantab, Omid, Seyed Aili Javad Moosavi, Mohammad Reza Farahnak, Maryam Dastoorpoor, and Hanieh Raji. 2022. “Role of CRP As a Marker for Discrimination of Exudative and Transudative Pleural Effusion”. Monaldi Archives for Chest Disease 92 (4).