The PRA is calculated for each monthly serum sample. In addition to determining how much or how little PRA a patient has, we need to know how specific the antibody is. That is, is the antibody specific to a particular HLA . For example, if you received a transfusion from a donor with HLA-A2, you may develop antibody to A2. That's antibody specificity.
Some patients have one or two antibody specificities, while others have numerous specificities.
We are able to determine the specificity at the same time which we test for the monthly PRA . For this reason, we mail a tube to the patient, for a blood sample, on a monthly basis. The most recent monthly sample is used as the current sample, and must always be included in the pretransplant crossmatch. Most frequently asked questions 1. HLA antibody levels can be high following a transfusion but then decrease significantly months later.