Table 1.
Accuracy Indices for Different Methods of Calculation Cut‐off Absorbance for HBsAg Test on Oral Fluid and Whole Saliva
| Cut‐off value | Specimen | Absorbance value | % sensitivity (95% IC) | % specificity (95% IC) | PPV (95% IC) | NPV (95% IC) | Accuracy % |
|---|---|---|---|---|---|---|---|
| CO1 | Oral fluid | 1.0 | 85.1 | 92.6 | 88.8 | 90 | 89.5 |
| (71.7–93.8) | (83.6–97.5) | (75.9–96.2) | (80.4–95.8) | ||||
| Whole saliva | 1.0 | 93.6 | 80.8 | 77.1 | 94.8 | 86.0 | |
| (82.4–98.6) | (69.5–89.4) | (64.1–87.2) | (85.6–88.9) | ||||
| CO2 | Oral fluid | 2.559 | 63.8 | 98.5 | 96.7 | 79.6 | 84.3 |
| (48.5–77.3) | (92.0–99.9) | (92.0–99.9) | (69.5–87.7) | ||||
| Whole saliva | 4.432 | 80.8 | 94.1 | 90.4 | 87.6 | 88.6 | |
| (66.7–90.8) | (85.6–98.3) | (77.3–97.3) | (77.8–94.2) | ||||
| CO3 | Oral fluid | 0.041 | 85.1 | 94.1 | 90.9 | 90.1 | 90.4 |
| (71.7–93.8) | (85.6–98.3) | (78.3–97.4) | (80.7–95.9) | ||||
| Whole saliva | 0.098 | 93.6 | 92.6 | 89.8 | 95.4 | 93.0 | |
| (82.4–98.6) | (83.6–97.5) | (77.7–96.6) | (87.2–99.0) |
PPV: Positive Predictive Value; NPV: Negative Predictive Value; Accuracy: TP+TN/TP+TN+FP+FN TP: True Positive; True Negative; False Positive; False Negative. CO1: Cut‐off value determined by the manufacturer; CO2: Cut‐off value determined by 3 standard deviations above the mean saliva absorbance of HBV seronegative samples (mean+3SD); CO3: Cut‐off value determined by the area under receiver operating characteristic (AUROC) curve analysis for saliva absorbance values.