Table 3.
Optimal cutoff values and performance of diagnostic measures
| Diagnostic measure | Optimal cutoff values | AUC | Sensitivity* | Specificity* | PPV* | NPV* | Accuracy* |
|---|---|---|---|---|---|---|---|
| ESR | 44 mm/hr | 73% | 92% (83%–100%) |
53% (38%–69%) |
76% (62%–89%) |
80% (67%–93%) |
77% (64%–90%) |
| CRP | 93 mg/L | 93% | 88% (77%–98%) |
100% (100%–100%) |
100% (100%–100%) |
83% (72%–95%) |
92% (84%–100%) |
| Synovial WBC | 12,800 cells/μL | 98% | 89% (81%–96%) |
100% (100%–100%) |
100% (100%–100%) |
88% (80%–96%) |
94% (88%–100%) |
| %PMN | 89% | 91% | 81% (71%–90%) |
90% (83%–97%) |
91% (84%–98%) |
79% (70%–89%) |
85% (76%–93%) |
* Ninety-five percent confidence intervals in parentheses; AUC = area under the receiver operating characteristic curve; PPV = positive predictive value; NPV = negative predictive value; ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; Synovial WBC = synovial fluid WBC count; %PMN = percentage polymorphonuclear cells.