- Blood provision: ABO-matched, same Rh group and Kell negative (avoid stimulating production of Rh / K antibodies)
- Remember that allo-antibodies are only formed against antigens which the patient does not express.
- If the transfusion does not raise the Hb as expected, then extend the phenotype to include Duffy, Ss and Kidd antigens.
| Patient Rhesus Phenotype | Rhesus Phenotype to Select |
|---|---|
| rr (dce/dce) | rr |
| R1r (DCe/dce) | E negative (R1R1, R1r, or rr) |
| R1R1 (DCe/DCe) | R1R1 |
| R1R2 (DCe/DcE) | Any Rh phenotype |
| R2r (DcE/dce) | C negative (R2R2, R2r, or rr) |
| R2R2 (DcE/DcE) | R2R2 |
- Once alloantibodies are excluded after adsorption studies, the hospital may select the same ABO, Rh and K phenotype units and use an immediate spin cross-match technique using un-adsorbed plasma for compatibility testing before issuing the blood. This applies for samples up to 72 hours from the previous transfusion.
- In cases where an allo-antibody is detected, an IAT cross-match must be done using adsorbed plasma.
- Blood issued using adsorbed plasma should be labelled as suitable, rather than compatible, as the adsorption process can weaken the reactivity of alloantibodies.
- In complex, multiply-transfused cases, consideration should be given to genotyping to determine the patient’s RBC phenotype, and phenotype-matched blood provided.
- Pan-agglutination may be seen in the following situations:
- Warm AIHA
- Allo-antibody against a high-frequency antigen
- Presence of anti-HI
- Bombay phenotype
- Presence of multiple alloantibodies
- Presence of autoantibodies and alloantibodies
Hi
do you meant using adsorbed plasma for IS crossmatching?
Hello, thanks for your question. It should be an IAT cross-match because the purpose is to look for clinically-significant alloantibodies which are active at 37°C. The process is not fool-proof, however as adsorbing out the autoantibody sometimes results in a weak alloantibody getting diluted to the point where it cannot be detected.