TABLE 2.
Performance of the Architect HIV Ag/Ab combination assay according to cutoff S/CO ratios
| Parameter | Value(s) based on cutoff S/CO ratio | ||
|---|---|---|---|
| Value of cutoff S/CO ratio | 1.0 | 6.6 | 8.8 |
| No. of positive initial screening test results (%) | 543 (0.350) | 216 (0.139) | 209 (0.135) |
| No. of false-positive results (%) | 346 (0.223) | 19 (0.012) | 13 (0.012) |
| No. of indeterminate results (%) | 4 (0.003) | 4 (0.003) | 4 (0.003) |
| No. of true HIV-positive results (%) | 157 (0.101) | 157 (0.101) | 156 (0.100) |
| No. of previously confirmed HIV-positive results (%) | 36 (0.023) | 36 (0.023) | 36 (0.023) |
| Specificity (%) | 100.00 | 100.00 | 99.36 |
| 95% confidence interval (%) | 97.02-100.00 | 97.02-100.00 | 95.97-99.97 |
| Positive predictive value (%) | 99.78 | 99.99 | 99.99 |
| 95% confidence interval (%) | 99.75-99.80 | 99.98-99.99 | 99.99-99.99 |
| No. of true HIV-positive results (%) | 31.21 | 89.70 | 92.31 |
| No. of previously confirmed HIV results (%) | 27.22-35.49 | 84.00-93.62 | 86.93-95.67 |