Changes

==Introduction==

==Introduction==

The radioimmunoassay (RIA) is a sensitive technique used to detect the presence of antigen in a sample using radiolabelled antibodies. Developed in the 1960's, the RIA proved a powerful tool in antigen detection, although the procedure was soon overtaken by ELISA, which utilise enzymes rather than radioactive labels. RIAs are still used today however, to measure:  

The radioimmunoassay (RIA) is a sensitive technique used to detect the presence of antigen in a sample using radiolabelled antibodies. Developed in the 1960's, the RIA proved a powerful tool in antigen detection, although the procedure was soon overtaken by ELISA, which utilises enzymes rather than radioactive labels. RIAs are still used today however, to measure:  

*Hormone levels in blood and tissue fluids

*Hormone levels in blood and tissue fluids

*Serum proteins

*Serum proteins