Procalcitonin and C-reactive protein (CRP) as predictors of radiographic pneumonia.
| All patients (n = 364) n % | Pneumonia (n = 48) n % | Non-pneumonic (n = 316) n % | P-value | Sensitivity | Specificity | PPV | NPV | Crude OR (95% CI) | |
|---|---|---|---|---|---|---|---|---|---|
| Procalcitonin >0.06 ng/ml | 139/357 (39) | 33/47 (70) | 106/310 (34) | <0.001 | 0.70 | 0.66 | 0.24 | 0.94 | 4.54 (2.33 to 8.84) |
| Procalcitonin >0.08 ng/ml | 77/357 (22) | 23/47 (49) | 54/310 (17) | <0.001 | 0.49 | 0.83 | 0.30 | 0.91 | 4.54 (2.39 to 8.64) |
| Procalcitonin >0.10 ng/ml | 41/357 (11) | 17/47 (36) | 24/310 (8) | <0.001 | 0.36 | 0.92 | 0.41 | 0.91 | 6.75 (3.27 to 13.96) |
| Procalcitonin >0.25 ng/ml | 15/357 (4) | 11/47 (23) | 4/310 (1) | <0.001 | 0.23 | 0.99 | 0.73 | 0.89 | 23.38 (7.07 to 77.25) |
| Procalcitonin >0.50 ng/ml | 8/357 (2) | 8/47 (17) | 0 (0) | <0.001 | 0.17 | 1.00 | 1.00 | 0.89 | ∞(−) |
| CRP ≥20 mg/l | 145/363 (40) | 35 (73) | 110/315 (35) | <0.001 | 0.73 | 0.65 | 0.24 | 0.94 | 5.02 (2.59 to 9.88) |
CRP = C-reactive protein. LRTI = lower respiratory tract infection. PPV = positive predictive value. NPV = negative predictive value. OR = odds ratio.