Table 2.

Comparing the AUC of CRP, NLR and their combination in predicting infection in the development and validation groups.

Variable	CRP ≥ 40 mg/L	NLR ≥ 7.41	Combined CRP and NLR	P value*
Development cohort (n = 620)
AUC (95% CI)	0.75 (0.71–0.80)	0.68 (0.63–0.73)	0.76 (0.72–0.81)	P1 = 0.57
P	< 0.001	< 0.001	< 0.001	P2 < 0.001
Sensitivity (%)	75	68	69
Specificity (%)	76	68	84
+ LR	3.08	2.06	4.18
− LR	0.33	0.5	0.37
Validation cohort (n = 154)
AUC (95% CI)	0.73 (0.63–0.83)	0.62 (0.51–0.73)	0.75 (0.66–0.84)	P1 = 0.62
P	< 0.001	0.03	< 0.001	P2 = 0.01
Sensitivity (%)	82	66	72
Specificity (%)	64	58	78
+ LR	2.26	1.58	3.24
− LR	0.29	0.6	0.36

*The receiver operating characteristic (ROC) curves in the development and validation groups were compared by DeLong’s method.

P₁-P value of combined CRP and NLR vs CRP ≥ 40 mg/L; and.

P₂-P value of combined CRP and NLR vs NLR ≥ 7.41.