The effect of cyclosporine concentration on the labeling efficiency of an in vitro technetium-99m red blood cell labeling procedure.

Objective: The purpose of this study was to determine if the presence of cyclosporine A (CsA) in whole-blood samples decreased labeling efficiency when an in vitro red blood cell labeling procedure is used. Methods: Red blood cells were labeled by an in vitro method which required sodium pertechnetate, disodium edetate (EDTA), stannous chloride and stopper down centrifugation. Labeling efficiencies were calculated and plotted. Results: When 2 J.Lg of stannous ion was used to label RBCs, no significant change in labeling efficiency was observed with different concentrations of CsA. Upon increasing the concentration of stannous ion per sample, no improvement in labeling efficiency was observed. Conclusion: Cyclosporine levels in the blood do not affect the labeling of red blood cells if 2 J.Lg of stannous ion per milliliter of patient whole blood are used. Quality RBC labeling with sodium pertechnetate is possible even when patients have high cyclosporine blood levels.