Interestingly, prothrombin time was significantly elevated in patients with pleural effusion (PT 13.8 vs. 12.3, p = 0.014) and, although not statistically significant, there was a trend towards higher D-dimer levels in the pleural effusion group (median 494 vs. 385, p = 0.067). This evidence concerns the gene F2 and Pleural effusion.