Table 6.

Comparison of Main Groups and Microorganisms, and Diagnostic Cutoff Values

Biomarkers	Bacteria vs ATP	Bacteria vs VIR	Gram Negative vs Gram Positive	Gram Negative vs ATP	L pneumophila vs S pneumoniae
CRP	NS	NS	NS	NS	24.9 vs 19.9a
					P = .01
PCT	1.12 vs 0.19b	1.12 vs 0.2c	0.62 vs 1.67	0.62 vs 0.19	NS
	P < .0001	P = .003	P = .02	P = .002
TNF-α	NS	29 vs 14d	NS	NS	49 vs 27e
		P = .03			P = .0002
IL-6	144 vs 43f	NS	NS	116 vs 43	NS
	P = .01			P = .04
IL-8	NS	NS	13 vs 6.5	NS	16 vs 6g
			P = .003		P = .003

E = specificity; NPV = negative predictive value; PPV = positive predictive value; S = sensitivity. See Table 1-3 legends for expansion of other abbreviations.

^aCRP ≥ 22 mg/dL as cutoff to compare L pneumophila and S pneumoniae: S, 70%; E, 59%; PPV, 27%; and NPV, 90%. AUC, 0.7 (0.6–0.8); P = .01.

^bPCT ≤ 0.5 mg/dL as cutoff to compare bacteria and atypical: S, 81%; E, 68%; PPV, 22%; and NPV, 97%. AUC, 0.8 (0.6–0.9); P < .0001.

^cPCT ≤ 0.5 mg/dL as cutoff to compare bacteria and virus: S, 89%; E, 68%; PPV, 12%; and NPV, 99%. AUC, 0.8 (0.7–0.9); P < .01.

^dTNF-α ≤ 27 pg/mL as cutoff to compare virus and bacterial: S, 78%; E, 51%; PPV, 7%; and NPV, 98%. AUC, 0.7 (0.6–0.9); P = .03.

^eTNF-α ≥ 30 pg/mL as cutoff to compare L pneumophila and S pneumoniae: S, 88%; E, 57%; PPV, 39%; and NPV, 94%. AUC, 0.7 (0.6–0.8); P = .001.

^fIL-6 ≤ 100 pg/mL as cutoff to compare bacteria and atypical: S, 81%; E, 56%; PPV, 17%; and NPV, 96%. AUC, 0.7 (0.6–0,8); P = .01.

^gIL-8 ≥ 15 pg/mL as cutoff to compare L pneumophila and S pneumoniae: S, 57%; E, 69%; PPV, 27%; and NPV, 89%. AUC, 0.7 (0.6–0.8); P = .004.