Table 3.
Clinical utility of postoperative WBC values in predicting early periprosthetic joint infection
| Test | A single postoperative WBC count > 9.95 × 106 cells/μL | A WBC increase > 29.5% of baseline | An increase in WBC > 2.95 × 106 cells/μL from baseline |
|---|---|---|---|
| True-positive | 19 | 19 | 18 |
| True-negative | 6597 | 4813 | 6903 |
| False-positive | 7657 | 9441 | 7351 |
| False-negative | 5 | 5 | 6 |
| Sensitivity | 79.2% | 79.2% | 75% |
| Specificity | 46.3% | 33.8% | 48.4% |
| Accuracy | 46.3% | 33.8% | 48.5% |
| PPV | 0.25% | 0.20% | 0.24% |
| NPV | 99.9% | 99.9% | 99.9% |
WBC = white blood cell; PPV = positive predictive value; NPV = negative predictive value.