Table 3.
Further evaluation of samples classified as HIV positive using the testing algorithm shown in Figure 1*.
| ID# | Rapid test 1b |
Rapid test 2c |
Rapid test 3d |
3rd-gen EIA | WB | WB Bands | BioRad 4th-gen |
BioRad S/COe |
Abbott 4th-gen |
Abbott S/COe |
Discrim assay |
Aptima testf |
Viral load (c/mL) |
ARV drugs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | R | R | R | R | Pos | -- | R | Max | R | 318.06 | R | n/a | 9,052 | No |
| 2 | R | NR | NR | NR | Ind | 31+/− | R | 9.93 | R | 6.06 | R | NR | <400 | No |
| 3a | n/a | NR | R | R | Pos | -- | R | Max | R | 111.27 | R | QNS | <400 | No |
| 4a | n/a | QNS | QNS | R | Pos | -- | R | Max | R | 970.75 | R | n/a | 1,280 | 3TC, NVP |
| 5 | NR | NR | R | R | Pos | -- | R | 6.54 | R | 9.06 | NR | n/a | 2,651 | No |
| 6a | n/a | R | NR | R | Pos | -- | R | 10.75 | R | 3.88 | R | NR | <400 | No |
| 7 | NR | NR | NR | R | Neg | -- | R | 9.41 | R | 5.54 | NR | n/a | 459,246 | No |
| 8a | n/a | QNS | NR | R | Neg | -- | R | 1.37 | NR | 0.17 | R | NR | <400 | No |
| 9 | NR | NR | R | NR | Ind | 24+/− | NR | 0.06 | R | 1.19 | R | NR | <400 | No |
| 10a | n/a | NR | NR | NR | Neg | -- | NR | 0.67 | R | 3.11 | R | NR | <400 | No |
| 11 | NR | QNS | NR | NR | Ind | 160+ | R | Max | R | 458.32 | R | R | <400 | No |
| 12 | NR | QNS | NR | NR | Ind | 160+/− | R | 11.53 | R | 2.58 | R | NR | <400 | No |
| 13 | NR | NR | R | NR | Ind | 18+/−, 31+/−, 160+ | R | Max | R | 11.53 | R | NR | <400 | No |
| 14 | NR | QNS | NR | NR | Ind | 160+/− | R | 8.61 | R | 3.00 | R | NR | <400 | No |
| 15 | NR | QNS | R | NR | Ind | 160+/− | R | 12.09 | R | 28.11 | R | NR | <400 | No |
| 16 | NR | QNS | QNS | NR | Ind | NA | R | 11.84 | R | 158.13 | R | NR | <400 | QNS |
| 17 | NR | QNS | NR | NR | Ind | 160+/− | R | 10.97 | R | 28.29 | R | NR | QNS | QNS |
| 18 | NR | QNS | NR | NR | Ind | 18+/−, 160+/− | R | Max | R | 44.53 | R | NR | <400 | No |
| 19 | NR | QNS | QNS | NR | Ind | NA | R | 13.67 | R | 56.00 | R | NR | <400 | No |
| 20 | NR | R | R | NR | Ind | 160+ | R | Max | R | 137.92 | R | NR | <400 | QNS |
| 21 | NR | QNS | R | NR | Ind | 160+ | R | 13.28 | R | 6.78 | R | NR | QNS | QNS |
| 22 | NR | R | NR | NR | Ind | 160+ | R | Max | R | 133.60 | R | NR | <400 | No |
| 23 | NR | QNS | NR | NR | Ind | 18+, 160+/− | R | Max | R | 71.17 | R | NR | <400 | No |
| 24 | NR | NR | NR | NR | Ind | 160+/− | R | Max | R | 55.89 | R | NR | <400 | No |
| 25 | NR | NR | R | NR | Ind | 160+ | R | 10.13 | R | 10.15 | R | NR | <400 | No |
| 26 | NR | QNS | NR | NR | Ind | 160+/− | R | 5.75 | R | 2.13 | R | NR | <400 | No |
| 27 | NR | NR | R | NR | Ind | 160+ | R | 13.19 | R | 4.02 | R | NR | <400 | No |
| 28 | NR | NR | R | NR | Ind | 160+, DB+/− | R | Max | R | 18.97 | R | NR | <400 | No |
| 29 | NR | NR | NR | NR | Neg | -- | R | 4.32 | R | 3.91 | R | NR | <400 | No |
The assays used for testing (see Methods) included: Rapid tests: Uni-Gold HIV Test; Uni-Gold Recombigen HIV Test; Oraquick 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; Aptima test: APTIMA HIV-1 RNA Qualitative Assay; Viral load: Roche COBAS AMPLICOR HIV-1 MONITOR test, v1.5 (validated modified assay for low-volume samples); 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; Discrim: discriminatory; c/mL: copies per milliliter; ARV: antiretroviral drug; R: reactive; NR: non-reactive; Pos: positive; Neg: negative; Ind: indeterminate; n/a: not applicable/not performed; QNS: quantity not sufficient (insufficient plasma available for testing); 3TC: lamivudine; NVP: nevirapine.
Cases 3, 4, 6, 8, and 10 are from South Africa; the rest of the cases are from Tanzania.
Rapid test 1: Uni-Gold HIV test; performed in Tanzania only.
Rapid test 2: Uni-Gold Recombigen HIV-1/2 Test (FDA-cleared); 13 samples did not have sufficient plasma for testing.
Rapid test 3: OraQuick ADVANCE® Rapid HIV-1/2 Antibody Test (FDA-cleared); 3 samples did not have sufficient plasma for testing.
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).
Samples were not tested with the Aptima HIV RNA assay if the viral load was >400 copies/mL.