Cell labelling with colloidal substances in whole blood.

A method for the labeling of leucocytes with 99mTc-colloid is described. The labelling can be done in samples of whole blood, because the colloid is only taken up by the phagocytosing cells, the monocytes and the granulocytes. The part of the colloid that is not phagocytosed is brought to a soluble state with Na-citrate, so that only the phagocytosed colloid is reinjected. The labelling efficiency with this method is between 80% and 90%. Measurements of the activity in the leucocytes 3 h after reinjection, have shown that at least 50% of the labelled cells are at this time still available in the blood pool. The clinical results on 32 patients with the tentative diagnosis of an abdominal abscess and on 42 patients with the tentative diagnosis of septic loosening of an endoprosthesis have shown that the labelled leucocytes are very well suited to show up local foci of inflammation.