The mean concentrations of pleural effusion lactate dehydrogenase (LDH), adenosine deaminase (ADA), protein, CEA and BNP were 246.0 U/L (range, 89.8–421.9 U/L), 13.8 U/L (range, 1.8–24.0 U/L), 42.6 g/dl (range, 32.8–52.6 g/dl) and 2.17 mg/mL (range, 0.46–4.31 mg/mL), and 1217.58 (range, 35.24–432.2 mg/mL), respectively (Table 3). Here, CEACAM5 is linked to Pleural effusion.