Table 2 Sensitivity, specificity, PPV and NPV according to different C-reactive protein (CRP) and procalcitonin (PCT) cut offs in the patients with excluded or definite community acquired pneumonia
Biomarkers' cut-off | Total | Excluded CAP | Definite CAP | p value | Se | Sp | PPV | NPV | LR+ | AUC |
|---|---|---|---|---|---|---|---|---|---|---|
(N = 169) | (N = 71) | (N = 98) | ||||||||
n (%) | n (%) | n (%) | ||||||||
CRP cut-off | ||||||||||
> 20 mg/L | 133 (79) | 41 (58) | 92 (94) | <0.001 | 93.9 | 42.2 | 69.2 | 83.3 | 1.62 | |
> 30 mg/L | 123 (73) | 35 (49) | 88 (90) | <0.001 | 89.8 | 50.7 | 71.5 | 78.2 | 1.82 | |
> 50 mg/L | 109 (64) | 26 (37) | 83 (85) | <0.001 | 84.7 | 63.4 | 76.1 | 75.0 | 2 .31 | 0.787 |
> 70 mg/L | 92 (54) | 24 (34) | 68 (69) | <0.001 | 69.4 | 66.2 | 73.9 | 61.0 | 2.05 | |
> 100 mg/L | 73 (43) | 15 (21) | 58 (59) | <0.001 | 59.2 | 78.9 | 79.4 | 58.3 | 2.80 | |
PCT cut-off | ||||||||||
> 0.10 μg/L | 115 (68) | 39 (55) | 76 (78) | 0.003 | 77.5 | 45.1 | 66.1 | 59.2 | 1.41 | |
> 0.25 μg/L | 74 (44) | 25 (35) | 49 (50) | 0.061 | 50.0 | 64.7 | 66.2 | 48.4 | 1.41 | 0.655 |
> 0.50 μg/L | 53 (31) | 16 (23) | 37 (38) | 0.044 | 37.7 | 77.5 | 69.8 | 47.4 | 1.67 | |
CRP >49.5 mg/L and PCT cut-off combined | ||||||||||
PCT > 0.13 μg/L | 83 (49) | 21 (29) | 62 (63) | <0.001 | 63.2 | 70.4 | 74.6 | 58.1 | 2.13 | |
PCT > 0.1 μg/L | 90 (53) | 22 (31) | 68 (69) | <0.001 | 69.4 | 69.0 | 75.5 | 62.0 | 2.23 | |
PCT > 0.25 μg/L | 68 (40) | 21 (29) | 47 (48) | 0.018 | 47.9 | 70.4 | 69.1 | 49.5 | 1.62 | |
PCT > 0.5 μg/L | 51 (30) | 15 (21) | 36 (36) | 0.041 | 36.7 | 78.9 | 70.6 | 47.4 | 1.74 | |