TABLE 2.
RNA levels from four to eight replicates of quantitative RNA assays using spiked plasma, breastmilk supernatant, and mock swab samples
| Virus used for spiking | Avg log10 RNA level/ml in plasmaa (% CVb) | Log10 RNA level
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Breast milk supernatant
|
Freezing medium
|
Freezing medium plus:
|
|||||||
| Swab
|
Swab and cells
|
||||||||
| Avg/ml (differencec) | % CV | Avg/ml (difference) | % CV | Avg/specimen (difference) | % CV | Avg/specimen (difference) | % CV | ||
| Clade A | 3.28 (12.42) | 3.17 (−0.11) | 21.14 | 3.36 (0.08) | 21.77 | 3.25 (−0.03) | 36.94 | 3.20 (−0.08) | 33.38 |
| Clade C | 3.00 (18.67) | 2.85 (−0.15) | 41.78 | 3.04 (0.04) | 8.67 | 2.70 (−0.30) | 31.37 | 2.81 (−0.19) | 13.69 |
| Clade D | 2.50 (23.07) | 2.18 (−0.32) | 24.44 | 2.47 (−0.03) | 51.00 | 2.27 (−0.23) | 42.72 | 2.32 (−0.18) | 33.65 |
a
The amount of clade A, C, and D virus added was estimated based on previous assays. Previous studies showed that the Gen-Probe HIV-1 viral load assay can accurately quantify all three subtype. Thus, differences in the spiked plasma reflect small differences in the amount of viral stock added.
b
CV, coefficient of variation.
c
Log10 difference between nonplasma samples and plasma samples is shown in parentheses.