Studies with biotinylated RBC: (1) use of flow cytometry to determine posttransfusion survival and (2) isolation using streptavidin conjugated magnetic beads.

Methods are reported for the quantitation and isolation of biotinylated red blood cells (B- RBC). The first method is for determination of posttransfusional survival of rabbit RBC by flow cytometry. The survival of B-RBC was measured using both fresh and paraformaldehyde-fixed cells with similar results. The posttransfusion survival of rabbit RBC measured in this way was normal. There was no indication of increased cell destruction due to antibodies directed against B-RBC and no evidence for loss of biotin from circulating cells. The second methodology is for the isolation of B-RBC from blood with streptavidin-coated magnetic beads. At least eighty percent of positive cells were recovered with very few false positives. Both methods may be helpful in the study of resealed erythrocytes.