Radiochemical quality control of 99mTc-labelled immunoglobulin G by immobilised protein A from staphylococcus aureus.

Large fractions of immunoglobulin G (IgG) from mammalian species show high affinities for protein A isolated from staphylococcus aureus. The radiochemical purity of 99mTc-labelled IgG was determined by means of protein A, covalently bound to sepharose, by a column radiochromatographic technique and by a simpler and more rapid technique in vials. Different labelling methods produced different radiochemical purities. Limitations and applications of the testing systems are discussed.