Characterization of Markers in Blood Tests of Patients With Pleural Effusion and Their Correlation to Different Etiologies.

Background: To investigate the etiology of pleural effusion, a variety of examinations are performed, including invasive ones: Thoracentesis is an invasive procedure to remove fluid or air from the pleural cavity for diagnostic or therapeutic purposes. Until now, there are no blood markers that can help us diagnose the type of pleural effusion without the need for pleural puncture or drainage.

Aims: The aim of this study was to investigate the relationship and the utility of the new inflammatory markers taken from complete blood count (CBC) to differentiate between the various types of pleural effusion before the invasive procedure decision.

Material And Methods: This is an observational retrospective study. Data was collected from medical records of patients aged 18-90 admitted in Ziv Medical Center, Safed, Israel that were diagnosed with pleural effusion from 2013 to 2019. Of those patients, of whom inflammatory markers from blood counts and thoracentesis results were obtained, the outcomes were compared with the diagnosis type of pleural effusion.

Results: This study involved 391 patients, 256 suffered from exudate type effusion, their median age was 72 years, while 135 suffered from transudate effusion, their median age was 80 years. Those with exudate effusion had higher levels of CRP, platelets, neutrophils, and lymphocytes in blood, whereas those with transudate effusion had higher levels of MPV and RDW in blood. Other blood markers such as NLR and PLR were not statistically significant, but were also higher in the blood of patients with exudate effusion.

Conclusion: An evaluation of simple and inexpensive measurements of blood count such as platelets, neutrophils, lymphocytes, MPV, RDW may provide insight into the etiology of pleural effusion.