Diagnostic value of suPAR in differentiating noncardiac pleural effusions from cardiac pleural effusions

Soluble urokinase plasminogen activator receptor ( suPAR ) is a newly discovered inflammatory biomarker. suPAR has not been previously studied in differentiating noncardiac pleural effusion ( PF ) from cardiac PF . The aim of our study was to assess the diagnostic value of suPAR in PF . Methods The concentration of PF ‐ suPAR was measured by a commercialized enzyme‐linked immunosorbent assay in a prospective cohort of 74 patients with PF , 18 patients with PF due to cardiac failure ( CF ) and 56 patients with noncardiac PF . The area under the curve quantified the overall diagnostic accuracy of the tests. Results The median pleural fluid suPAR level was found as 23 (5.4–102.8) ng/mL. The median PF ‐ suPAR level in CF was significantly lower than that of noncardiac effusions [11.8 (5.4–28.9) ng/m L vs 26.7 (8.2–102.8) ng/m L , respectively, P  < 0.001]. The area under the receiver operating characteristic curve was 0.878 (95% confidence interval: 0795–0.962, P  < 0.001) for noncardiac pleural fluid suPAR . The sensitivity, specificity and positive predictive value of PF ‐ suPAR for noncardiac effusions at the cutoff level of ≥17.6 n/mL was 88%, 83% and 94%, respectively. The suPAR level in PF was found to correlate with all of the biochemical parameters of PF. Conclusions suPAR is a potential new marker for the discrimination between cardiac and noncardiac PF .