Introduction: Ultratag® is a red blood cell (RBC) labelling kit that removes the need to wash the cells while maintaining a high efficiency label. However conventional use of Ultratag®, using a vial and syringes, has the potential risk of infection associated with handling blood products. The objective of this experiment was to employ a syringe system using components of Ultratag®, to label and heat-damage RBCs whilst maintaining high labelling efficiency.

Method: The contents of Ultratag® kit components including the reaction vial were reproduced in syringes. 6 blood samples, 5 mL each were obtained from volunteers and labelled with approximately 140MBq of 99mTc-O4- each using this syringe system. Prior to heating the RBCs 1ml of blood was removed to determine the pre heating labelling efficiency of each sample. The remaining labelled RBCs were heated in a water bath for 20 minutes at 50oC. Pre and post heat labelling efficiencies were determined for each sample. A blood smear from one blood sample, pre and post heat, was obtained to determine the percentage of RBCs damaged during labelling.

Results: The average labelling efficiency for pre and post heating was 99.63% and 98.11% respectively. The blood smear found that 60% of the blood had been denatured.

Discussion: The closed syringe RBC labelling provided heat damaged RBCs with high labelling efficiency in a reduced time, increasing department productivity. The decreased blood manipulation through use of a closed system have the added benefit of decreasing the risks associated with labelling blood to both patients and technologists.