EXPERIENCES WITH THE ENZYME-MULTIPLIED IMMUNOASSAY CYCLOSPORINE SPECIFIC ASSAY IN A THERAPEUTIC DRUG-MONITORING LABORATORY

Cyclosporin-A (CsA) monitoring is well established in the management o f most organ transplant patients. The present communication reviews th e performance of the recently introduced specific enzyme-multiplied im munoassay (EMIT) CsA method during the first 7 months of its operation and compares costs of providing this service with those of the specif ic I-125 radioimmunoassay (RIA) method previously employed in this cli nical laboratory. Results suggest that the EMIT method performed well, giving long calibration curve stability (up to 12 weeks), and only 4. 4% of the 31 kits through this period were consumed in assaying calibr ation standards compared with 20.8% with RIA. However, more quality co ntrol assays were performed, with the net result that only a slight im provement in the percentage of kit consumed in patient assays was note d (74.0% compared with 70.3%) with the EMIT method. This method appear s to have been well accepted clinically as the CsA assay request rate over this period increased by 23% and, since it is both specific and r apid, is, therefore, recommended as the best CsA method currently avai lable.