Suggested approach to phenotype matching
| History of hyperhemolysis? | None | Yes. Consider avoiding transfusion when possible∗ | |||
| Previous transfusions | ≤20 RBCus† | >20 RBCus† | ≤20 RBCus† | >20 RBCus† | |
| Historical and current antibodies | No antibodies | RH-K matching w/wo case-by-case extended pheno matching‡ | RH-K matching | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching |
| Antibodies to RH-K and WAAs | RH-K matching | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching | ||
| AUSs | RH-K matching + monitor the antibody screen closely for an emerging antibody | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching | ||
| NOAs | RH-K matching | RH-K and extended pheno matching, plus consider matching for the NOA if it is active at 37°C and/or had developed after transfusion | RH-K matching w/wo case-by-case extended pheno matching, plus consider matching for the NOA if it is active at 37°C and/or had developed after transfusion | ||
| AEP | RH-K and extended pheno matching | ||||
| History of hyperhemolysis? | None | Yes. Consider avoiding transfusion when possible∗ | |||
| Previous transfusions | ≤20 RBCus† | >20 RBCus† | ≤20 RBCus† | >20 RBCus† | |
| Historical and current antibodies | No antibodies | RH-K matching w/wo case-by-case extended pheno matching‡ | RH-K matching | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching |
| Antibodies to RH-K and WAAs | RH-K matching | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching | ||
| AUSs | RH-K matching + monitor the antibody screen closely for an emerging antibody | RH-K and extended pheno matching | RH-K matching w/wo case-by-case extended pheno matching | ||
| NOAs | RH-K matching | RH-K and extended pheno matching, plus consider matching for the NOA if it is active at 37°C and/or had developed after transfusion | RH-K matching w/wo case-by-case extended pheno matching, plus consider matching for the NOA if it is active at 37°C and/or had developed after transfusion | ||
| AEP | RH-K and extended pheno matching | ||||
Based on this and previous work,5,18,42,59 in a setting with a predominantly European donor pool, with RH-K matching. The exact threshold can be adjusted for specific donor and patient populations.
pheno, phenotype; w/wo, with or without.
Consider using immunosuppressive drugs such as rituximab.5
The threshold observed in this study may vary in other populations, and individual risk may be subject to variation.
Conditions for high risk of hyperhemolysis include acute, inflammatory situations and patients who received <12 RBCus.18