Table 4.

Performance of procalcitonin for detecting patients with bacterial infection at various cutoff values (± 95%CI)

PCT (ng/ml)	PCT > 0.5	PCT > 1.35	PCT > 2	PCT > 5
Bacterial infection prevalence = 48.7%
Sensitivity	1.00 ± 0.00	0.81 ± 0.11	0.67 ± 0.12	0.50 ± 0.13
Specificity	0.63 ± 0.12	0.77 ± 0.11	0.82 ± 0.08	0.90 ± 0.08
Positive predictive value	0.72 ± 0.06	0.77 ± 0.10	0.78 ± 0.08	0.83 ± 0.15
Negative predictive value	1.00 ± 0.00	0.81 ± 0.11	0.72 ± 0.08	0.65 ± 0.08
Positive likelihood ratio	2.70	3.52	3.72	5.00
Negative likelihood ratio	0.00	0.25	0.40	0.56
Younden's index	0.63	0.58	0.49	0.40