Biochemical examination of pleural effusion: Glucose: 5.52 mmol/L (the normal range is 3.9–6.1 mmol/L); Protein: 36.5 g/L (the normal range is 20–40 g/L); Albumin: 22.2 g/L (the normal range is 20–40 g/L); Chlorine: 111.3 mmol/L (the normal range is 110-130 mmol/L); Pleural LDH: 220 U/L (the normal range is 230–460 u/L); Adenosine deaminase (ADA):9U/L(the normal range is 0–18 u/L). Here, ADA is linked to Pleural effusion.