K Safarcík1, H Brozmanová, V Bartos, A Jegorov, M Grundmann. 1. Department of Nuclear Medicine, University Hospital and Medico-Social Faculty, University of Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic. kristian.safarcik@fnsp.cz
Abstract
BACKGROUND: The aim of the work was to evaluate the possibility to estimate the level of cyclosporin A (CyA) metabolites as the difference of radioimmunoassay (RIA) non-specific and RIA specific methods. METHODS: Blood samples of renal transplant patients were analyzed by three different methods: RIA specific method (CYCLO-Trac, DiaSorin, USA) (RIA(SP)), RIA non-specific method (Immunotech, Czech Republic) (RIA(NS)), and high performance liquid chromatography (HPLC) method. RESULTS: Although values obtained by RIA(SP) correlated well those obtained by HPLC (RIA(SP)=0.995.HPLC+9.68; r(2)=0.962, n=448), the results of HPLC methods were lower by 8%. The values obtained by RIA(NS) were 2.57 times higher than the values obtained by RIA(SP) (RIA(SP)=0.356RIA(NS); r(2)=0.713, n=448). The ratio (CyA+CyA metabolites)/(CyA) calculated as the ratio RIA(NS)/RIA(SP) values for 42 renal transplant patients was relatively stable for each particular patient. The sum of selected CyA metabolites (M1+M17+M21) measured by HPLC correlated well with that estimated from the difference of RIA(NS)-RIA(SP): HPLC(metab)=0.921.(RIA(NS)-RIA(SP))+21.3; (r(2)=0.746, n=448). CONCLUSION: The combination of both the specific and non-specific methods for the determination of CyA presents an improved means for the TDM of CyA and CyA metabolites in renal transplant patients. Moreover, a combination of both methods can help to elucidate some unexpected events, such as the persistence of high cyclosporin blood levels.
BACKGROUND: The aim of the work was to evaluate the possibility to estimate the level of cyclosporin A (CyA) metabolites as the difference of radioimmunoassay (RIA) non-specific and RIA specific methods. METHODS: Blood samples of renal transplant patients were analyzed by three different methods: RIA specific method (CYCLO-Trac, DiaSorin, USA) (RIA(SP)), RIA non-specific method (Immunotech, Czech Republic) (RIA(NS)), and high performance liquid chromatography (HPLC) method. RESULTS: Although values obtained by RIA(SP) correlated well those obtained by HPLC (RIA(SP)=0.995.HPLC+9.68; r(2)=0.962, n=448), the results of HPLC methods were lower by 8%. The values obtained by RIA(NS) were 2.57 times higher than the values obtained by RIA(SP) (RIA(SP)=0.356RIA(NS); r(2)=0.713, n=448). The ratio (CyA+CyA metabolites)/(CyA) calculated as the ratio RIA(NS)/RIA(SP) values for 42 renal transplant patients was relatively stable for each particular patient. The sum of selected CyA metabolites (M1+M17+M21) measured by HPLC correlated well with that estimated from the difference of RIA(NS)-RIA(SP): HPLC(metab)=0.921.(RIA(NS)-RIA(SP))+21.3; (r(2)=0.746, n=448). CONCLUSION: The combination of both the specific and non-specific methods for the determination of CyA presents an improved means for the TDM of CyA and CyA metabolites in renal transplant patients. Moreover, a combination of both methods can help to elucidate some unexpected events, such as the persistence of high cyclosporin blood levels.