Table 1 Comparison of the parameters of the five different types of pleural effusion

Demographic data:

 Age, years

48 (17–86)

66 (42–90)

60 (37–79)

62 (25–88)

57.5 (44–82)

 Male blood biomarkers:

22 (66.7%)

13 (52.0%)

17 (89.47%)

17 (62.96%)

3 (37.5%)

 WBC, cells/μL

5500 (2700–10,400)

6700** (3800–16,000)

9790** (4400–30,700)

8260** (4000–16,100)

6385 (3600–10,100)

 CRP, mg/L

37.75 (3.77–135.87)

24.22 (0.76–128.03)

108.79** (23–208.1)

41.4 (1.08–293.4)

5.14** (0.32–19.28)

 S-Alb, g/dL

33.3 (24.6–40.3)

33.7 (23.1–44.3)

31.8 (24.2–39.3)

31.8 (23.7–40.8)

34.8 (23.3–40.6)

 S-LDH, U/L

161 (97–605)

172 (120–302)

169 (120–860)

186 (108–990)

199.5 (144–455)

Pleural fluid biomarkers

 Total cell counts, cells/ul

4800 (416–20,000)

4120 (500–197,164)

7007 (950–290,000)

2400 (120–500,000)

1604 (100–9885)

 pH

7.5 (1–8.5)

7 (5.5–8.7)

7 (6–8.5)

7.5 (6.5–9)

7.55 (6.5–8.5)

 TP, g/dL

49.2 (27.4–59.6)

47.8 (30.9–60.6)

45.3 (5.1–62.3)

33.6** (15.9–58.3)

40.05 (15.5–54.1)

 PF-Alb, g/dL

27.1 (18.2–34.7)

27.5 (17–34.7)

23.4* (2.7–31.5)

20** (1.9–43.7)

22* (9–25.4)

 Glu, mmol/L

4.96 (0.16–11.1)

5.84 (2.67–11.03)

2.95 (0.09–11.86)

6.77** (0.25–12.78)

6.125* (5.29–12)

 PF-LDH, U/L

532 (144–1783)

377 (150–2078)

1607** (731–10,613)

277** (68–1169)

136.5** (62–354)

 ADA, U/L

48 (20.6–81.5)

8.9** (5.1–25.4)

32.9 (12–115.4)

8.9** (1.4–19.5)

11.2** (1.2–22.4)

Ratios between two biomarkers: only the parameters with P value < 0.01 between any two groups are included

 WBC/CRP

123.82 (26.5–1298.1)

307.89 (87.62–8026.32)

112.63 (53.34–363.91)

202.81 (27.88–4259.26)

1206.23 (254.15–24,062.50)

 WBC/TP

113.38 (77.09–204.38)

146.63 (94.13–393.12)

217.62 (132.13–5039.22)

257.86** (88.80–763.44)

135.21 (93.26–651.61)

 WBC/PF-Alb

201.33 (118.77–352.54)

255.73 (155.20–804.02)

509.32** (221.11–9518.52)

400.00** (169.12–3789.47)

304.03 (145.16–1122.22)

 WBC/Glu

1138.06 (444.44–17,837.84)

1244.90 (536.91–5914.29)

3627.12 (758.85–122,280.95)

1293.63 (328.64–28,800)

861.09 (573.25–1909.26)

 WBC/PF-LDH

11.02 (1.51–38.19)

20.27 (2.94–85.33)

6.15** (1.92–13.12)

37.56** (6.95–135.29)

42.43 (17.51–124.19)

 WBC/ADA

119.80 (41.1–271.84)

648.94 ** (194.87–2509.80)

325.23 (140.81–744.93)

957.27** (369.23–4272.72)

473.78 (264.79–8416.67)

 CRP/TP

0.83 (0.08–2.91)

0.55 (0.02–3.15)

2.44 (0.37–34.95)

1.20 (0.02–10.92)

0.17 (0.01–0.0.44)

 CRP/PF-Alb

1.47 (0.15–6.97)

0.89 (0.03–6.43)

4.72** (0.73–66.02)

2.22 (0.04–55.97)

0.32 (0.01–0.79)

 CRP/ADA

0.89 (0.14–3.94)

1.97 (0.08–16.06)

3.75 (0.55–10.73)

6.85 (0.09–105.04)

0.58 (0.11–2.40)

 CRP/Glu

9.55 (0.69–179.08)

4.21 (0.10–45.73)

38.7 (6.54–891.44)

5.50 (0.13–425.40)

0.86** (0.03–3.42)

 TP/PF-Alb

1.8 (1.01–2.39)

1.74 (1.42–2.76)

1.89 (1.63–2.54)

1.71 (0.55–8.89)

1.83 (1.36–2.63)

 TP/Glu

9.61 (4.52–212.5)

7.81 (3.91–15.58)

14.96 (3.95–412.22)

5.05** (1.52–67.6)

6.31 (2.44–9.08)

 TP/ADA

0.98 (0.52–2.42)

5.24 (1.60–9.37)

1.20 (0.15–3.34)

4.28** (1.2–11.36)

3.94 (2.28–12.92)

 PF-Alb/Glu

5.69 (2.38–113.75)

4.27 (1.94–10.94)

6.51 (2.08–162.22)

2.59** (1.03–8.71)

3.47** (1.7–4.31)

 PF-Alb/ADA

0.56 (0.28–1.29)

2.77 (0.78–5.29)

1.20 (0.15–3.34)

2.43** (0.19–8)

2.22** (0.92–7.5)

 PF-LDH/TP

11.43 (2.67–52.44)

7.45 (3.14–49.95)

6.51 (2.08–162.22)

6.60 (3.21–61.3)

3.314 (1.97–9.35)

 PF-LDH/CRP

15.66 (2.79–159.42)

12.88 (1.95–1109.71)

17.15 (4.48–117.26)

8.69 (0.62–198.15)

36.36 (8.09–193.75)

 PF-LDH/PF-Alb

17.74 (4.43–97.97)

12.63 (5.45–80.80)

72.92** (27.17–1245.56)

10.37 (5.95–545.26)

6.07* (2.87–17.18)

 PF-LDH/Glu

106.02 (21.98–11,143.75)

54.25 (18.46–778.28)

767.32 (75.89–36,596.55)

35.62 (8.69–4144.00)

23.67 (5.17–59.4)

PF-LDH/ADA

12.27 (4.48–29.34)

38.23 (8.31–183.89)

62.97 (29.87–133.92)

32.92** (12.14–101.57)

14.00 (7.43–120.83)

 ADA/Glu

9.58 (2.69–410.63)

1.29 (0.70–9.07)

12.12 (1.72–397.93)

1.25** (0.21–40.8)

1.59** (0.23–3.76)