TABLE 4.
Sensitivity of the centrifugation Amplicor assay
| Amt of input HIV-1 RNA (no. of copies/tube)a | Mean (range) OD for HIV-1 RNA | DFb | Mean (range) OD for IQS | DF | No. of pools positive for RNA/total no. tested |
|---|---|---|---|---|---|
| 50.0 | 0.49 (0.33–0.62) | 5 | 0.80 (0.60–0.93) | 5 | 5/5 |
| 25.0 | 0.27 (0.19–0.40)c | 5 | 0.66 (0.53–0.82) | 5 | 5/5 |
| 12.5 | 0.89 (0.42–1.81) | 1 | 0.86 (0.76–1.00) | 5 | 5/5 |
| 6.25 | 0.41 (0.16–0.64)d | 1 | 0.81 (0.77–0.87) | 5 | 4/5 |
| 0.00 | 0.07 (0.06–0.07) | 1 | 0.80 (0.75–0.87) | 5 | 0/5 |
Pools of 1.5 ml containing 59 serum samples that were antibody and HIV-1 RNA negative were mixed with 25 μl of dilutions of serum from an HIV-1-infected individual with known numbers of HIV-1 RNA copies per milliliter and were tested in quintuplicate. During the same experiment a 1/20 dilution of an HIV-1-positive serum sample included in the pool was tested by the HIV-1 Amplicor Monitor test in triplicate, and 2,008 HIV-1 RNA copies/ml were found; the expected value was 2,000 RNA copies/ml.
DF, dilution factor.
For the only pool for which the OD was <0.2 (OD, 0.19) at a dilution of 1/5, the OD was 0.72 at a dilution of 1/1.
The OD was <0.2 (OD, 0.16) for only one sample, i.e., was negative according to the manufacturer’s instructions.