The Effect of Cyclosporine on Technetium-99m Red Blood Cell Labeling Using the Ultratag® RBC In Vitro Kit

Abstract

Objective: The purpose of this investigation is to determine if cyclosporine (CsA) interferes with Technetium-99m red blood cell (^99mTc-RBC) labeling when using the Ultratag® in vitro RBC kit.

Methods: The investigators set up a dilution study using increasing cyclosporine concentrations with whole blood samples. Whole blood samples from four heart transplant patients on maintenance CsA medication were also radiolabeled to investigate labeling efficiencies.

Results: Cyclosporine did not interfere with ^99mTc-RBC radiolabeling as labeling efficiencies were found to be ≥95% in both the dilution and patient studies.

Conclusions: Although CsA does not inhibit ^99mTc-RBC radiolabeling of whole blood when using the Ultratag kit, the investigators hypothesize that CsA may interfere with the label if kit levels of stannous ion were to be decreased.