Table 2. Performance of Shannon entropy as a measure for identifying recent HIV-1 infections.
| HIV-1 env segment | Diversity measure | Optimal Cut-off value | HIV-1 Subtype | AUC | AUC (95% CI) | TPR (Sn) |
TNR (Sp) |
N recent/chronic |
|---|---|---|---|---|---|---|---|---|
| GP120-C2_1 | Shannon entropy | 0.054 | Multiple | 0.806 | [0.752–0.861] | 82% | 69% | 134/115 |
| GP120-C2_3 | Shannon entropy | 0.059 | Multiple | 0.805 | [0.749–0.862] | 90% | 67% | 134/115 |
| GP120-V3 | Shannon entropy | 0.083 | Multiple | 0.812 | [0.758–0.866] | 87% | 66% | 134/115 |
| GP120-C2_1 | Shannon entropy | 0.054 | B | 0.791 | [0.726–0.856] | 80% | 69% | 106/86 |
| GP120-C2_3 | Shannon entropy | 0.06 | B | 0.810 | [0.747–0.873] | 91% | 66% | 106/86 |
| GP120-V3 | Shannon entropy | 0.083 | B | 0.831 | [0.773–0.889] | 90% | 66% | 106/86 |
| GP120-V3 | Shannon entropy | 0.083 | Multiple:WB+/MAA+specimens as recent | 0.801 | [0.740–0.863] | 89% | 66% | 80/115 |
| GP120-V3 | Shannon entropy | 0.097 | Multiple: p24+ specimens as recent | 0.827 | [0.763–0.891] | 93% | 60% | 54/115 |
| GP120-C2_1 | Shannon entropy | 0.06 | Multiple: p24+ specimens as recent | 0.850 | [0.794–0.905] | 93% | 66% | 54/115 |
| GP12-C2_3 | Shannon entropy | 0.048 | Multiple: p24+ specimens as recent | 0.844 | [0.786–0.902] | 91% | 71% | 54/115 |
TPR (true positive rate) = sensitivity: recent HIV-1+ specimens correctly classified,
TNR (true negative rate) = specificity: chronic HIV-1+ specimens correctly classified. The optimal cutoff value indicates the proportion of patients correctly classified and represented the highest TPR (recency) + TNR (chronic) or (Sensitivity+ Specificity).