TABLE 2.
Characteristics of BK virus (BKV) standards
| Manufacturer | Bio-Rad (Exact Diagnostics) | Antylia (ZeptoMetrix) | Thermo Fisher Scientific (AcroMetrix) | NIBSC |
|---|---|---|---|---|
| Product name | BKV Verification Panel | NATtrol BK Virus Linearity Panel | AcroMetrix BKV Panel | First WHO International Standard for BK virus (14/212) |
| Viral strain | Dunlop, subtype Ia | Gardner | Not disclosed | BKV 1b-2 |
| Matrix | EDTA Plasma | Purified protein matrix | EDTA Plasma | Lyophilized equivalent of 1 mL solution of 10 mM Tris-HCL (pH 7.4), 0.5% human serum albumin, and 0.1% D-(+)-Trehalose dehydrate |
| Extractable (y/n) | Yes | Yes | Yes | Yes |
| Manufacturer nominal value unit assignment | Five 10-fold concentrations provided, 2.30 to 7.30 log10 IU/mL | Five 10-fold concentrations provided, 4.00 to 8.00 log10 copies/mL | Five 10-fold concentrations provided, 2.70 to 6.70 log10 copies/mL | 7.20 log10 IU/mL |
| Means of viral load assignment (primary quantitative measurement) | ddPCR (Droplet Digital PCR) |
qPCR | qPCR | Consensus value assignment (33 laboratories) |