Diagnostic accuracy indices of laboratory and diagnostic imaging studies performed at the index and re-evaluation visits for the association with a significant change in therapy
| N | Sensitivity (95% CI) | Specificity (95% CI) | NPV (95% CI) | PPV (95% CI) | LR− | LR+ | |
| Imaging studies at re-evaluation visit | 305 | 82.4 (71.2 to 90.5) | 73.0 (66.9 to 78.5) | 93.5 (89.6 to 96.0) | 46.7 (40.9 to 52.6) | 0.24 (0.14–0.41) | 3.05 (2.41–3.86) |
| Increase in CRP ≥25 mg/L | 142 | 66.7 (51.6 to 79.6) | 76.6 (66.7 to 84.7) | 81.8 (74.8 to 87.2) | 59.3 (49.0 to 68.8) | 0.44 (0.29–0.66) | 2.85 (1.88–4.32) |
| CRP at index visit >27 mg/L | 305 | 45.6 (33.5 to 58.1) | 73.0 (66.9 to 78.5) | 82.4 (78.8 to 85.5) | 32.6 (25.8 to 40.3) | 0.75 (0.59–0.94) | 1.69 (1.21–2.36) |
| Increase in CRP ≥25 mg/L and imaging studies at re-evaluation | 88 | 94.1 (71.3 to 99.9) | 69.7 (57.3 to 80.1) | 98.0 (87.7 to 99.7) | 43.2 (34.4 to 52.6) | 0.08 (0.01–0.57) | 3.09 (2.12–4.50) |
| Increase in CRP ≥25 mg/L and imaging studies at re-evaluation and CRP at index visit ≥27 mg/L | 36 | 51.9 (32.0 to 71.3) | 88.9 (51.8 to 99.7) | 38.1 (28.1 to 49.2) | 93.3 (68.0 to 98.9) | 0.54 (0.34–0.85) | 4.67 (0.71–30.68) |
CRP, C reactive protein; LR+, positive likelihood ratio; LR−, negative likelihood ratio; NPV, negative predictive value; PPV, positive predictive value.