Table 3.

Logistic regression models for the diagnosis of infectious pleural effusion

	Model 1			Model 2
	Coefficients (SE)	P	OR (CI 95%)	Coefficients (SE)	P	OR (CI 95%)
Leukocytes (cells/µl×103)	0.0611 (0.0239)	0.0105	1.06 (1.01-1.11)	0.0732 (0.026)	0.0000	1.07 (1.02-1.13)
Neutrophils (%)	0.0331 (0.0051)	0.0000	1.03 (1.02-1.04)	0.0299 (0.005)	0.0000	1.03 (1.02-1.04)
	Cutoff			Cutoff
CRP PF (mg/dL)		0.0000			0.0000
IL-6 PF (pg/mL)	0.003		Reference	0.003		Reference
	0.5		1.39 (1.01-1.94)	0.5		1.67 (1.10-2.52)
	1		1.94 (1.56-2.40)	1		2.78 (2.11-3.65)
	2		3.62 (2.89-4.52)	2		6.97 (4.99-9.73)
	3		6.05 (4.41-8.30)	3		13.44 (8.78-20.60)
	5		11.26 (7.33-17.30)	5		23.08 (13.57-39.23)
	10		20.32 (11.31-36.50)	10		29.18 (13.79-61.75)
	15		31.72 (12.98-77.52)	15		31.11 (9.37-103.18)
	20		44.70 (9.36-213.2)	20		26.54 (3.88,181.48)
	25		72.16 (2.41-2159.7)	25		89.77 (1.10-3248.18)
					0.0126
				4000		Reference
				10,000		1.35 (0.80-2.28)
				50,000		0.87 (0.351-1.50)
				100,000		1.76 (0.92-3.36)
				500,000		96.45 (5.92-1570)
				1,000,000		662 (4.20-104267)

Model 1=Includes leukocyte count, percentage of segmented neutrophils, and reactive C-protein values in pleural fluid. Intercept=−4.4310, R²=0.547, brier=0.105, AUC=0.898, Model 2=Includes leukocyte count, percentage of segmented neutrophils and reactive C-protein, and IL-6 values in pleural fluid. Intercept=−4.4619, R²=0.582, brier=0.097, AUC=0.907. OR=Odds ratio, CI=Confidence intervals, AUC=Area under the curve, SE=Standard error, IL-6=Interleukin 6, PF=Pleural fluid, PF=Pleural fluid