Radioactive isotope assay

[milenko]

Can some please give me the definition of what "Radioactive isotope assay" is and what it is for?

Just curious

[mwbeah]

Can some please give me the definition of what "Radioactive isotope assay" is and what it is for?

Just curious

An assay is the analysis of a substance or mixture to determine its constituents or their level. In Life Sciences, it is also the estimation of strength of a drug or substance by comparing its effects in test animals to a reference standard.

A radioisotope is an unstable radioactive isotope that decays to a stable state by emitting radiation

Radioimmunoassay

Radioimmunoassay refers to a method of measuring hormones in the blood. Most hormones are present in extremely minute quantities, and require a highly sensitive technique such as this. In radioimmunoassay, an antibody is developed that is highly specific for the hormone being measured. A small quantity of the antibody is mixed with a quantity of fluid (usually plasma) containing the hormone to be measured. Standard hormones, tagged with a radioactive isotope, are also added to the mixture. There is not enough antibody to bind with both the tagged hormone and with the hormone to be measured. The natural hormone and the tagged hormone compete for binding sites. The quantity of each of the hormones that binds is proportional to the concentration of each. After binding has reached equilibrium, the quantity of radioactive hormone bound with antibody is measured. If a large amount of radioactive hormone has bound with antibody, then only a small amount of natural hormone was available to compete with the radioactive hormone.