Which technique is NOT useful in distinguishing autoantibodies from high PRA alloantibodies?

The technique that is not useful in distinguishing autoantibodies from high PRA alloantibodies is NIH-CDC analysis on frozen cell trays. This method primarily assesses the presence of antibodies against specific antigens but lacks the specificity required to differentiate between autoantibodies, which are antibodies directed against one’s own tissues, and high PRA alloantibodies, which are typically directed against foreign histocompatibility antigens due to previous transfusions or pregnancies.

In contrast, other techniques mentioned serve distinctly different purposes. Platelet absorption, for instance, focuses on utilizing platelets to bind and absorb certain antibodies, which can help to isolate and identify autoantibodies versus alloantibodies. DTT treatment is effective in denaturing certain antibodies, thereby aiding in the characterization of the antibody specificity. Flow cytometry allows for a detailed analysis of antibody binding to cells, which can be crucial in identifying the presence and type of antibodies present in the serum.

Thus, while NIH-CDC analysis is keen on detecting general antibody presence, it does not provide the distinct information necessary for differentiating between autoantibodies and high PRA alloantibodies, rendering it less useful in this specific context.