Table 3.
Intra-laboratory Variability of the CMV Viral Load Assay
| CMV viral load intra-lab coefficient of variation (CV) (%) |
||||
|---|---|---|---|---|
| Member 1 | Member 2 | Member 3 | Member 4 | |
| Laboratory | 2.70 log copies/ml | 3.70 log copies/ml | 4.70 log copies/ml | 5.70 log copies/ml |
| 1 | 3.85 | 3.60 | 2.60 | 0.96 |
| 2 | * | * | 2.74 | 1.51 |
| 3 | 6.14 | 5.58 | 2.37 | 4.07 |
| 4 | 9.62 | 2.51 | 0.30 | 6.94 |
| 5 | 7.35 | 4.31 | 5.07 | 5.94 |
| 6 | 7.20 | 6.67 | 2.81 | 1.15 |
| 7 | 6.39 | 1.01 | 0.85 | 2.20 |
| 8 | 5.19 | 2.29 | 1.70 | 2.38 |
| 9 | 3.45 | 3.40 | 0.64 | 0.30 |
| 10 | 4.28 | 2.22 | 0.95 | 1.83 |
| 11 | 14.05 | 0.56 | 0.95 | 1.07 |
| 12 | 5.30 | 12.33 | 6.67 | 3.46 |
| 13 | 5.97 | 1.94 | 1.89 | 1.41 |
| 14 | 6.11 | 3.14 | 2.11 | 3.30 |
| 15 | 16.16 | 1.76 | 4.02 | 3.53 |
| 16 | 14.87 | 8.81 | 3.52 | 4.68 |
| 17 | * | 3.27 | 1.85 | 2.04 |
| 18 | 2.54 | 0.53 | 2.29 | 2.02 |
| 19 | * | 3.78 | 11.56 | 2.71 |
| 20 | 9.16 | 1.28 | 3.07 | 1.07 |
| 21 | 14.35 | 9.42 | 4.25 | 0.25 |
| 22 | 2.88 | 22.84 | 2.21 | 0.72 |
| 23 | 4.50 | 1.30 | 0.72 | 0.62 |
| Average CV (%) | 7.47 | 4.66 | 2.83 | 2.35 |
| Mean VL (log) | 2.96 | 3.81 | 4.77 | 5.66 |
| 95% CI of VL (log) | 2.53–3.39 | 3.46–4.16 | 4.51–5.03 | 5.40–5.92 |
| Log Change: 95% CI | 0.87 | 0.70 | 0.53 | 0.52 |
| Fold Change: 95% CI | 7.4 | 5.0 | 3.4 | 3.3 |
*
Samples with undetectable CMV were excluded from the analysis.