In histocompatibility testing, what does the term Prozone refer to?

The term Prozone refers specifically to a scenario in histocompatibility testing where there are elevated levels of antibodies that can lead to false negative crossmatch results. This phenomenon occurs because the concentration of antibodies is so high that it prevents the formation of adequate antigen-antibody complexes necessary for detection in the assay. The excess antibodies can interfere with the specific binding required for an effective reaction, thus masking the presence of sensitization.

In the field of histocompatibility, it is crucial to ensure accurate matching between donor and recipient tissues, as discrepancies can lead to graft rejection or complications. Recognizing the Prozone effect is critical in designing assays and interpreting results, as it highlights the need for careful dilution of serum samples to ensure that antibody concentrations fall within the optimal range for crossmatch testing. This understanding aids in troubleshooting and ensuring that accurate determinations of compatibility are made.