The objective of the present study was to explore possibility of using reconstituted British Reference Standard (BRP) (Catalogue No. Y0000488) beyond its recommended shelf life for studying molecular size distribution in human normal intravenous immunoglobulin so as to reduce wastage, expenses and minimize the dependency on such BRP. Though the initial HPLC test results revealed that BRP after reconstitution retains required relative retention time of dimer and monomer up to 309 and 374 days when stored at 2-8oC and -10ºC respectively whereas leaflet of instruction for BRP recommends its use, after reconstitution, maximum up to 14 days when storing at 4oC but without freezing. Present study suggests that BRP of molecular size after reconstitution and stored properly may be used beyond the recommended shelf life of 14 days and till the required relative retention time of dimer and monomer is retained by BRP.