Abstract
Recently TDX analyzer®(ABBOTT Lab.)for the therapeutic drug monitoring system has been available, which is based on the method of fluorescence polarization immunoassay. We have used this system for assays of four antiepileptic drugs, i. e. phenytoin, phenobar-bital, carbamazepine and valproic acid. We described here the investigation of this system especially for feasibility, accuracy and interference with mesaurement by various plasma components.
The reproducibility of consecutive measurements and that between measurements at different time was satisfactory for every assays. Using same standard curve that was made on the first day, measured levels of the control serum drugs were stable for two weeks. Consequently, it was not necessary to redraw up standard curve every day. This is one of the merits in this system.
Concerning the interference with measurement by serum components, 7% undere-stimation of carbamazepine level was obtained in the sample to which high dose of lipid (triglyceride 389 mg/dl and total cholesterol 525 mg/dl) was added. Therefore, we should take care of measurement of chyloid plasma.
To compare this system with EMIT system®(enzyme immunoassay) which has been already widely used, the simultaneous determinations of the level of the above antiepileptic drugs were done in fifty epileptic patients, and we found that its correlation was excellent.
Our data demonstrated that TDX analyzer possessed certain advantages in terms of accuracy, precision, quickness and simplicity.
