Pooled sera for cytotoxicity testing: accurate, time- and cost-effective preliminary crossmatches

To conserve sera, reduce technologist time and facilitate distribution of kidneys to the most likely recipient from groups of highly sensitized patients, we studied the feasibility of using pooled sera in preliminary crossmatches. From 16 chronic renal failure patients, 275 sera were studied against fresh cell panels from 24 to 35 donors. Using the antiglobulin crossmatch technique, sera were studied individually, in consecutive pools of five and in consecutive pools of 10. Reactions of component sera were assessed on a cell-by-cell comparison with their pools of five and 10 sera. Crossmatches performed with pools of five sera and pools of 10 sera detected the same cytotoxic reactions as did their component sera in 97.6% and 97.8% of the reactions, respectively. We conclude that 10 sera can be pooled so that preliminary crossmatch testing of all positive sera of all theoretically potential allograft recipients can be accomplished with accuracy and efficiency, even in the larger regional distribution centers.