Applications:

The technique offers several advantages, most important of them being sensitivity and specificity. Very small quantity of the sample (less than 0.1 mL) is required for the measurement. Analysis by RIA does not require any sample preparation or prior extraction of the analyte except the separation of blood serum. Samples may be collected at remote places far away from laboratory and sent for analysis at a central palce. Being an in vitro technique no radioactivity enters into patient's body. Substances routinely determined using radioiodine labeled antigens include thyroid related hormones (T3, T4, TSH), digestive hormones(gastrin), sex hormones (FSH, LH, HCG), insulin and other compounds  as listed in Table.

Table:  Selection of Compounds Analyzed by RIA