Table 1.
Characteristics of the Cobas 6800 BKV test and Real-Q BKV quantification assay. The contents of this table are based on the manufacturers’ product specifications.
| Cobas 6800 BKV Test | Real-Q BKV Quantification Assay * | |
|---|---|---|
| Principle | Real-time quantitative PCR | Real-time quantitative PCR |
| Sample type | Plasma and urine | Serum, plasma, and urine |
| Sample volume | ||
| Plasma | 375 uL | 320 uL |
| Urine | 575 uL | 320 uL |
| Total duration | ~180 min | ~280 min (120 min for DNA extraction, 40 min for pipetting, and 120 min for amplification) |
| Hands-on time | - | ~40 min (thawing reagents and aliquoting and mixing) |
| Assay targets | VP2 and small t-antigen | VP1 |
| Subtypes detected | Ia, Ic, II, III, and IV | Not specified |
| Limit of detection | ||
| Plasma | 21.5 IU/mL | 71.4 IU/mL (183 copies/mL) |
| Urine | 12.2 IU/mL | Not specified |
| Linear range | ||
| Plasma | 21.5 IU/mL to 1 × 108 IU/mL | 195 IU/mL to 1.95 × 1012 IU/mL (500 copies/mL to 5 × 1012 copies/mL) |
| Urine | 200 IU/mL to 1 × 108 IU/mL | Not specified |
| Imprecision | ||
| Plasma | 6.92–25.74%CV | 11.58%CV |
| Urine | 4.61–11.55%CV | Not specified |
* Analytical performance of the Real-Q BKV quantification assay was converted from copies/mL to IU/mL, using the conversion factor (0.39) provided by the manufacturer. Abbreviations: BKV, BK virus; CV, coefficient of variation; PCR, polymerase chain reaction; VP, viral protein.