Table 1 Comparison of pool and individual Abbott RealTime HIV-1 viral load testing results for 447 specimens re-tested individually from all pools with a result of HIV-1 detected, conducted as part of method validation prior to scale-up of pooled testing for all routine specimens. Following this method validation, ≥ 40 copies/ml for a pooled result was chosen as the cut-off for re-testing each specimen in a positive pool; this was chosen to improve testing efficiency while minimizing the chance for misclassification of an unsuppressed specimen as suppressed.
Pool result (copies/mL) | Individual result (copies/mL) | Total | Number (%) that would be misclassified as suppressed* | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Undetectable | Suppressed, detectable | Unsuppressed | ||||||||||
0 | < 40 | 40–119 | 120–199 | 200–1000 | 1001–5000 | 5001–10,000 | 10,001-100,000 | > 100,000 | ||||
< 40 | 149 | 28 | 27 | 2 | 1 | 207 | 0/207 | 0% | ||||
40–119 | 46 | 7 | 7 | 7 | 5 | 72 | 0/72 | 0% | ||||
120–199 | 10 | 2 | 2 | 2 | 5 | 21 | 0/21 | 0% | ||||
200–1000 | 19 | 8 | 2 | 8 | 5 | 42 | 5/42 | 12% | ||||
1001–5000 | 17 | 5 | 2 | 1 | 6 | 3 | 2 | 36 | n/a | |||
5001–10,000 | 7 | 1 | 2 | 2 | 3 | 15 | ||||||
10,001-100,000 | 19 | 4 | 1 | 7 | 5 | 36 | ||||||
> 100,000 | 9 | 1 | 2 | 6 | 18 | |||||||
Total | 276 | 55 | 42 | 13 | 22 | 11 | 5 | 12 | 11 | 447 | ||
