EFFECT OF DIFFERENT ANTICOAGULANTS ON THE LABELING OF RED-BLOOD-CELLS AND PLASMA-PROTEINS WITH TC-99(M)

There are controversies about the effect of different anticoagulants on the labelling of blood elements with Tc-99(m). Our results show that the type of anticoagulant employed to withdraw the whole blood can modify the Tc-99(m) labelling of red blood cells (RBC) and plasma proteins (PP). The anticoagulants ACD (citric acid, sodium citrate and dextrose solution), heparin and sodium oxalate present similar results for the Tc-99(m) labelling of RBC with the exception of 0.13 mu M stannous chloride. In this assay oxalate provides the best RBC labelling. In addition, with ethylenediaminetetraacetic acid (EDTA) the labelling of RBC is almost always lower than with the other anticoagulants, probably due to its high chelating capacity. The anticoagulants ACD, oxalate and heparin show the same results as expected with Tc-99(m) labelling of PP. The lowest labelling at 13.00 mu M stannous chloride in the presence of oxalate is probably due to its low chelating capacity. The results also reinforce the idea that the erythrocyte membrane exerts an important role in the regulation of stannous ion transport into RBCs.