ABSTRACT
Currently, immunoassays are widely used for therapeutic drug monitoring (TDM) in clinical laboratories. Immunoassays measure the analyte concentration in a specimen by forming a complex with a specific binding molecule, which in most cases is an analyte-specific antibody (or a pair of specific antibodies). In the 1970s and 1980s immunoassays were introduced for TDM, replacing tedious chromatographic methods. Currently over 25 immunoassays are commercially available for analysis of various therapeutic drugs in clinical laboratories. Different formats are used for immunoassay design and more than one commercial vendor may use a similar format (Table 3.1). Most immunoassay methods use specimens without any pretreatment and assays can be performed on fully automated, continuous, random access analyzers. The assays use very small amounts of sample volume (< 100 µL), reagents can be stored in the analyzer and calibration curves can be electronically stored in the analyzer.
