InVitro Labeling of RBCs (Ultra-Tag)

  1. Labeling
    1. Collect 1-3 mL of blood using heparin or ACD as an anticoagulant.
    2. Transfer the anticoagulated blood to the reaction vial and gently mix to dissolve the contents of the vial.
    3. Allow to react for 5 minutes.
    4. Add the contents of syringe number 1 (sodium hypochlorite solution) and mix by gentle inversions 4-5 times.
    5. Add contents of syringe number 2 (citric acid, sodium citrate, and dextrose solution) to the reaction vial and mix by gentle inversions 4-5 times.
    6. Add 10-100 mCi of sodium pertechnetate to the reaction vial in a maximum of 3 mL volume.
    7. Mix by gently inverting vial 4-5 times.
    8. Allow to react for 20 minutes and agitate occasionally by gently swirling.
    9. Mix gently prior to withdrawing the patient’s dose. The labeled RBCs should be administered within 30 minutes of preparation or as soon as possible thereafter.

  2. Radiochemical purity
    1. Transfer 0.2 mL of the red blood cell solution into a vial.
    2. Add 2 mL of 0.9% sodium chloride solution.
    3. Gently agitate vial.
    4. Centrifuge for 5 minutes.
    5. Separate the supernatant from the cells and determine the percent of the activity which remains with the red blood cells.
    6. The radiochemical purity should be greater than 90%.

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