[Enzyme immunoassay of drug in blood (serum)]

Antiepileptic drugs, cardiac glycosides (digoxin, etc.), theophylline, antiarrhythmic agents (quinidine, procainamide, lidocaine, etc.) and aminoglycosides have narrow therapeutic range and large interindividual variations have been reported for their pharmacokinetics. Therefore, to obtain the appropriate therapeutic effects without undesirable effects, monitorings of above drug concentrations are useful (therapeutic drug monitoring). There are many assay methods (high-performance liquid chromatography, immunoassay, enzyme immunoassay, etc.) to determine drugs in serum. In those assays various enzyme immunoassays, enzyme-multiplied immunoassay technique (EMIT), enzyme-linked immunosorbent assay (ELISA), apoenzyme reactivation immunoassay (ARIS), radial partition immunoassay (RPIA), etc., are developed and widely used in many clinical laboratories. These assay systems offer convenience and great rapidity of assay and satisfactory accuracy and reproducibility but lack a little specificity of antibody.