Table 4.
Evaluation of a subset of samples classified as HIV negative using the testing algorithm shown in Figure 1.*
| ID | Rapid testb |
3rd-gen EIA |
WB | WB Bands | BioRad 4th-gen |
BioRad S/COc |
Abbott 4th-gen |
Abbott S/COc |
Discrim assayd |
Aptima HIV RNA |
ARV drugs |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | R | NR | n/a | -- | NR | 0.26 | NR | 0.15 | n/a | NR | None |
| 2 | R | NR | n/a | -- | NR | 0.25 | NR | 0.18 | n/a | NR | QNS |
| 3 | R | NR | n/a | -- | NR | 0.03 | NR | 0.10 | n/a | NR | None |
| 4 | R | NR | n/a | -- | NR | 0.20 | NR | 0.13 | n/a | NR | None |
| 5 | NR | R | Neg | -- | NR | 0.63 | NR | 0.14 | NR | NR | None |
| 6a | n/a | R | Neg | -- | NR | 0.21 | NR | 0.29 | NR | NR | None |
| 7 | NR | NR | Ind | n/a | R | 4.06 | NR | 0.67 | NR | NR | QNS |
| 8 | NR | NR | Neg | -- | R | Max | NR | 0.12 | NR | NR | None |
| 9 | NR | NR | Neg | -- | R | 6.91 | NR | 0.17 | NR | NR | QNS |
| 10a | n/a | NR | Neg | -- | R | 1.32 | NR | 0.75 | NR | NR | QNS |
| 11a | n/a | NR | Neg | -- | NR | 0.27 | R | 1.12 | NR | NR | QNS |
| 12 | NR | NR | Pos | -- | R | 1.39 | R | 57.52 | NR | NR | None |
| 13 | NR | NR | Ind | n/a | R | Max | R | 14.09 | NR | NR | QNS |
| 14 | NR | NR | Ind | 18+/− | R | 12.71 | R | 14.30 | NR | NR | QNS |
| 15 | NR | NR | Ind | 160+/− | R | 11.54 | R | 13.07 | NR | NR | QNS |
| 16 | NR | NR | Ind | 160+/− | R | 11.15 | R | 2.62 | NR | NR | None |
| 17 | NR | NR | Ind | 18+/−, 160+/− | R | 13.39 | R | 33.29 | NR | NR | None |
| 18 | NR | NR | Ind | 18+, 160+/− | R | 7.85 | R | 2.15 | NR | NR | None |
| 19 | NR | NR | Ind | 160+/− | R | 6.18 | R | 2.72 | NR | NR | None |
| 20 | NR | NR | Ind | 160+/− | R | 3.50 | R | 17.66 | NR | NR | QNS |
| 21 | NR | NR | Ind | 160+/− | R | 9.94 | R | 1.84 | NR | NR | QNS |
| 22 | NR | NR | Neg | -- | R | 7.12 | R | 3.45 | NR | NR | None |
| 23 | NR | NR | Neg | -- | R | 3.43 | R | 1.40 | NR | NR | QNS |
| 24 | NR | NR | Neg | -- | R | 10.53 | R | 5.37 | NR | NR | QNS |
Samples included in this table had at least one reactive serologic assay (in addition to the one of the two HIV rapid tests initially performed at study sites). The assays used for testing (see Methods) included: Rapid test: Uni-Gold HIV Test; 3rd-gen EIA: VITROS Anti-HIV 1+2 assay; WB: Genetics System HIV-1 Western Blot; Bio-Rad 4th-gen: GS HIV Combo Ag/Ab EIA; Abbott 4th-gen: ARCHITECT HIV Ag/Ab Combo assay; Discrim assay: Multispot HIV-1/HIV-2 Rapid Test; RNA assay: APTIMA HIV-1 RNA Qualitative Assay; ARV assay: qualitative multi-drug screening assay that detects 15 ARV drugs.
Abbreviations: ID#: sample identification number; 3rd-gen: third generation; EIA: enzyme immunoassay; WB: Western blot; 4th-gen: fourth-generation; S/CO: signal-to-cutoff ratio; Discrim: discriminatory; ARV: antiretroviral drug; R: reactive; NR: non-reactive; n/a: not applicable/not performed; Neg: negative; Ind: indeterminate; QNS: quantity not sufficient (insufficient plasma available for testing).
Cases 6, 10 and 11 are from South Africa; the rest of the cases are from Tanzania.
The HIV rapid test (third test, tie-breaker) was performed in Tanzania only; all other testing was performed at the HPTN Laboratory Center in Baltimore, MD, USA.
The signal/cutoff ratio (S/CO) is considered non-reactive if the value is <1. For the GS HIV Combo Ag/Ab EIA assay, a reactive sample with an absorbance over the plate reader is reported as having a maximal S/CO (Max).
The discriminatory assay was not performed if in-country HIV rapid tests were the only tests with reactive/positive test results.