Diagnostic Values of Different Cutoff Levels
| Comparison | Cutoff (μm) | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|---|
| HC vs AET > 6% | 1.12 | 64.1% | 66.7% | 90.9% | 26.3% |
| HC vs esophagitis in UGE | 1.13 | 73.3% | 73.3% | 93.2% | 35.5% |
| HC vs all GERD | 1.12 | 63.5% | 66.7% | 93.6% | 19.2% |
| HC vs all GERD | 1.39 | 20.0% | 100.0% | 100.0% | 12.2% |
PPV, positive predictive value; NPV, negative predictive value; HC, healthy control; AET, acid exposure time; UGE, upper gastrointestinal endoscopy; GERD, gastroesophageal reflux disease.