Table 2: Comparison of The COBAS Ampliprep/COBAS Taqman HIV-1 Test v2 (Standard assay) with an ultra-centrifugation step prior to the standard protocol (Ultrasensitive assay) in two separate dilution series (Panel 1 and 2). Input copies/ml are theoretical concentrations calculated from a dilution series originated from a plasma sample quantified by COBAS Ampliprep/COBAS Taqman HIV-1 Test, version 2. All samples were run in quadruplicate (1-4), once in each dilution step.
Panel 1 | Standard assay | Ultrasensitive assay | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Input copies/ml | 1 | 2 | 3 | 4 | Mean copies/ml | SD | CV | 1 | 2 | 3 | 4 | Mean copies/ml | SD | CV |
2683 | 3284 | 2332 | 3599 | 3915 | 3283 | 684 | 21 | 1942 | 1862 | 1257 | 1639 | 1675 | 307 | 18 % |
537 | 686 | 660 | 572 | 637 | 639 | 47 | 8 % | 554 | 607 | 459 | 148 | 442 | 205 | 46 % |
107 | 130 | 126 | 132 | 84 | 118 | 23 | 19 | 94 | 52 | 61 | - | 69 | 22 | 32 % |
26.8 | < 20 | < 20 | 23 | < 20 | - | - | 24 | 47 | 20 | 13 | 26 | 15 | 57 % | |
5.4 | < 20 | - | 30 | < 20 | - | - | 5.4 | 6.2 | 5.6 | - | 5.7 | 0.4 | 7 % | |
2.7 | < 20 | - | - | < 20 | - | - | Det | Det | 6.1 | Det | - | - |
Panel 2 | Standard assay | Ultrasensitive assay | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Input copies/ml | 1 | 2 | 3 | 4 | Mean copies/ml | SD | CV | 1 | 2 | 3 | 4 | Mean copies/ml | SD | CV |
27 | 50 | 36 | 200 | 78 | 91 | 75 | 82 % | 103 | 105 | 104 | 59 | 93 | 23 % | 24 % |
9 | < 20 | 44 | < 20 | 29 | 36.5 | 11 | 29% | 32 | 27 | 43 | 24 | 31 | 8.3 | 27% |
3 | - | - | - | < 20 | - | 14 | 5.1 | 7 | 8.7 | 4.7 | 54% | |||
1 | - | - | - | - | 3.2 | - | 2.1 | 2.2 | 2.5 | 0.6 | 24% |
SD: Standard Deviation; CV: Coefficient of Variation; Det: Detected but not quantified by the ultrasensitive assay; < 20: Detected but not quantified by the standard assay (The COBAS Taqman HIV-1 test, version 2.0 from Roche).