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Statistical characteristics of the X-ray diffraction test.
| Feature | All participants (n = 1796) | Participants aged < 70 (n = 1627) |
|---|---|---|
| Sensitivity | 64% | 74% |
| Specificity | 77.6% | 78% |
| Positive predictive value | 6% | 5.4% |
| Negative predictive value | 99% | 99.4% |
| Accuracy | 77.3% | 77.9% |
| Likelihood ratio of a positive test | 2.8 | 3.3 |
| Likelihood ratio of a negative test | 0.05 | 0.3 |
