Abstract:

Objective To evaluate the consistency of homogeneous enzyme immunoassay and enzyme-amplified immunoassay in the determinations of phenytoin,valproic acid,theophylline,digoxin,methotrexate,carbamazepine and mycophenolic acid in serum and cyclosporine A in whole blood with 8 drug concentrations. Methods Homogeneous enzyme immunoassay and enzyme-amplified immunoassay were used to determine BIO-RAD with 3 concentrations and original quality control products,and the within-run and between-run precisions were calculated. A total of 120 clinical samples were collected for each drug concentration,which more than 30% of them were abnormal. Except for cyclosporine A,30 homologous plasma samples were collected for each drug concentration. Using SIEMENS ADVIA 2400 automatic biochemical analyzer,homogeneous enzyme immunoassay and enzyme-amplified immunoassay were performed parallelly,and the consistency of them was evaluated. Results The within-run and between-run precisions of homogeneous enzyme immunoassay and enzyme-amplified immunoassay were good,and there was a good stability. The overall correlation of each drug concentration was good,and r were 0.997 for cyclosporine A,0.993 for phenytoin,0.997 for valproic acid,0.996 for theophylline,0.988 for digoxin,0.994 for methotrexate,0.999 for carbamazepine and 0.997 for mycophenolic acid. All the regression equations were significant statistically （P<0.001）. There was no statistical significance for the results of the 2 methods（P>0.05）. The expected bias of each drug concentration at medical decision level was in allowable error range. The consistency of homologous serum and plasma samples was good,except for cyclosporine A,and each regression equations were significant statistically（P<0.01）,and the difference of paired t-test was not significant statistically （P>0.05）. Conclusions The results of phenytoin,valproic acid,theophylline,digoxin,methotrexate,carbamazepine,mycophenolic acid and cyclosporine A with 8 drug concentrations have good consistency between the 2 methods by SIEMENS ADVIA 2400 automatic biochemical analyzer.

Key words: Homogeneous enzyme immunoassay, Enzyme-amplified immunoassay, Biochemical instrument, Drug concentration, Consistency