Table 1.
Probability of Ab Matching Cognate Antigen in Recipients
| HLA antibody class | Screening Cutoff selected for determining a positive result | Average CPRAa: Percentage of Recipients Expected to Have Cognate Antigen(s) SAB Category (# of Reactive SABs) |
|||||
|---|---|---|---|---|---|---|---|
| 1 SAB b | 2 SAB b | 3 SAB b | 4 SAB b | >4 SAB b | Total | ||
| Class I | >3 SD | 16.0 | 20.8 | 28.1 | 34.8 | 54.8 | 38.6 |
| >4 SD | 12.2 | 19.4 | 30.2 | 35.7 | 56.2 | 45.7 | |
| >5 SD | N/A | 31.0 | 28.5 | 27.0 | 67.9 | 63.9 | |
| Class II | >3 SD | 23.5 | 38.5 | 48.4 | 55.0 | 76.3 | 47.0 |
| >4 SD | 23.5 | 38.4 | 48.1 | 54.5 | 76.1 | 49.0 | |
| >5 SD | 22.8 | 37.5 | 47.5 | 54.8 | 76.2 | 53.9 | |
a
CPRA calculator (http://www.unos.org/resources ) was used to calculate the probability of an antibody-antigen match for recipients of each donation that had one or more reactive beads on the SAB assay. Donations with specificities not on the calculator (e.g. Cw3) were excluded from this analysis.
b
Reactive SABs were defined as those have MFI > 2500 for Class I beads or MFI > 1500 for Class II beads (Endres 2010).