Table 4 Diagnostic performance of urine and saliva for detecting Plasmodium antigens with reference to blood
Diagnostic indices | Urine specimens | Saliva specimens |
|---|---|---|
Overall indices of urine and saliva samples with blood contamination | ||
True positive | 134 | 217 |
True negative | 325 | 325 |
False positive | 0 | 0 |
False negative | 247 | 164 |
Sensitivity (95% CI) | 35.2% (30.38–40.20) | 57.0% (51.81–61.99) |
Specificity (95% CI) | 100% (98.87–100) | 100% (98.87–100) |
Accuracy (95% CI) | 65.0% (61.37–68.53%) | 76.8% (73.51–79.87%) |
PPV (95% CI) | 100.0 | 100.0 |
NPV (95% CI) | 56.8% (55.00–58.62) | 66.46% (63.84–68.99) |
χ2 goodness of fit (p-value) | 347.8 (< 0.05) | 153.3 (< 0.05) |
Diagnostic indices of urine and saliva samples without blood contamination | ||
True positive | 22 | 28 |
True negative | 325 | 325 |
False positive | 0 | 0 |
False negative | 269 | 182 |
Sensitivity (95% CI) | 7.6% (4.8–11.2%) | 13.3% (9.1–18.7%) |
Specificity (95% CI) | 100% (98.9–100) | 100% (98.9–100) |
Accuracy (95% CI) | 50.2% (46.2–54.2) | 53.3% (49.0–57.6) |
PPV (95% CI) | 100% | 100% |
NPV (95% CI) | 48.1% (47.2–48.9) | 49.7% (48.3–51.0) |