Table 1.
Biomarker values
| Biomarker | AUC (95% CI) | Cut-off value | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|---|---|
| O2 requirement >3 L/min | ||||||
| PCT (μg/L) | 0.836 (0.724, 0.948) | 0.5 | 56.3 | 94.3 | 81.8 | 82.5 |
| Ferritin (μg/L) | 0.791 (0.659, 0.922) | 772 | 75.0 | 68.4 | 55.6 | 83.9 |
| Glycosylated ferritin rate (%) | 0.745 (0.619, 0.872) | 40 | 95 | 55.3 | 52.8 | 95.5 |
| AST (IU/L) | 0.754 (0.616, 0.892) | 38 | 70.0 | 71.1 | 56.0 | 81.8 |
| ALT (IU/L) | 0.759 (0.635, 0.882) | 40 | 65.0 | 76.3 | 59.1 | 80.6 |
| Lymphocyte count (/mm3) | 0.718 (0.572, 0.863) | 540 | 42.1 | 97.4 | 88.9 | 77.1 |
| Hemoglobin (g/dL) | 0.645 (0.482, 0.808) | 12.1 | 60.0 | 63.2 | 46.2 | 75 |
| Disease severity | ||||||
| PCT (μg/L) | 0.787 (0.655, 0.919) | 0.5 | 46.2 | 86.8 | 54.6 | 82.5 |
| Ferritin (μg/L) | 0.709 (0.554, 0.864) | 772 | 64.7 | 60.9 | 40.7 | 80.7 |
| Glycosylated ferritin rate (%) | 0.698 (0.563, 0.837) | 40 | 94.1 | 51.2 | 44.4 | 95.5 |
| AST (IU/L) | 0.670 (0.510, 0.830) | 38 | 58.8 | 63.4 | 40 | 78.8 |
| ALT (IU/L) | 0.725 (0.591, 0.860) | 40 | 64.7 | 73.2 | 50 | 83.3 |
| Lymphocyte count (/mm3) | 0.728 (0.570, 0.885) | 540 | 50 | 97.6 | 88.9 | 83.3 |
| Hemoglobin (g/dL) | 0.718 (0.553, 0.883) | 12.1 | 70.6 | 68.3 | 48.0 | 84.9 |
| Progression to death | ||||||
| PCT (μg/L) | 0.759 (0.576, 0.943) | 0.5 | 50.0 | 82.2 | 27.3 | 92.5 |
| Ferritin (μg/L) | 0.658 (0.394, 0.923) | 772 | 57.1 | 54.9 | 14.8 | 90.3 |
| Glycosylated ferritin rate (%) | 0.674 (0.486, 0.861) | 40 | 100 | 43.1 | 19.4 | 100 |
| AST (IU/L) | 0.657 (0.424, 0.889) | 38 | 57.1 | 58.8 | 16.0 | 90.9 |
| ALT (IU/L) | 0.679 (0.488, 0.870) | 40 | 57.1 | 64.7 | 18.2 | 91.7 |
| Lymphocyte count (/mm3) | 0.861 (0.728, 0.995) | 540 | 71.4 | 92.0 | 55.6 | 95.8 |
| Hemoglobin (g/dL) | 0.779 (0.529, 1.0) | 12.1 | 85.7 | 62.8 | 24 | 96.9 |
Bold font indicates the best biomarker
AUC area under the curve, PPV positive predictive value, NPV negative predictive value, BMI body mass index, CRP C-reactive protein, PCT procalcitonin, AST aspartate aminotransferase, ALT alanine aminotransferase