Safe storage in lyophilised state of 131I-labelled albumin particles Inappropriate temperature during storage and shipping, respectively, affects the quality of labelled protein preparations disadvantageously. After lyophilisation the human serum albumin macroaggregate, labelled with iodine isotopes, retains its original properties provided it is lyophilised within 24 hr after its production. It can be resuspended completely, the size of the particles and the content of free iodine stay unchanged. Storage at 20°C for 14 days does not affect the quality of the lyophilised product. It is an expedient method to retain the properties of protein type radiopharmaka.