The need for standardization of methodology and components in commercial radioimmunoassay kits

The problems arising from the increasing use of commercial kits in radioimmunoassay (RIA) and related fields are discussed. These problems differ according to the substance under test. The quality of individual reagents is often good, but the methodology is often not optimal and may contain short-cuts which, although commercially attractive, can lead to erroneous values and poor sensitivity and precision. Minor modifications in the methodology often lead to big improvements in sensitivity and precision. This has been demonstrated in three digoxin kits employing antibody-coated tube techniques and in four kits for thyrotropin (TSH) using different techniques. It has also been noted that with many quality-control sera imported from the USA no values are ascribed to European kits for the components listed, thus reducing these sera to the function of precision control. The study underlines the need to standardize kit components and assay methods to enable the results obtained by different laboratories with different kits to be compared. (author)