| External calibrator used for value adjustment | Mean between-assay CV (%) (SD) |
| None (initial concentration) | 22.8 (4.6) |
| Both BNP-32 and glycosylated proBNP | 5.6 (3.9) |
| BNP-32 only | 31.9 (7.3) |
| Glycosylated proBNP only | 15.5 (2.6) |