Zucchelli G C, Pilo A, Chiesa M R, Scarlattini M, Bizollon C A
Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, Pisa, Italy.
Ther Drug Monit. 1996 Jun;18(3):273-9. doi: 10.1097/00007691-199606000-00009.
Beginning in 1987, an external quality assessment (EQA) scheme for cyclosporine (CsA) assay was organized by our Institute and supported by National Research Council (CNR); in 1991, the CNR EQA joined the French CsA interlaboratory program organized by Service de Radiopharmacie et Radioanalyse, University of Lyon. During the last 2 years (1993 and 1994 cycles), > 170 laboratories (from seven European countries) participated in this survey, assaying 44 control samples prepared from pooled blood of heart- and renal-transplant patients; normal pools added with known amounts of CsA were also distributed. During the whole EQA period, a trend toward the use of specific and nonisotopic techniques has been observed. In 1994, 91% of the collected results have been produced by specific methods [high-pressure liquid chromatography (HPLC) or specific immunoassays developed to assay the native molecule of CsA without its metabolites];in the same cycle, the fully automated techniques [TDx, fluorescence polarization immunoassay (FPIA), and enzyme-multiplied immunoassay (EMIT)] accounted for 73% of total results. CsA concentration measured by monoclonal specific immunoassays [(TDx FPIA, radioimmunoassay (RIA) Cyclo-Trac, and EMIT] was well correlated with those from HPLC (r = 0.99-1.00); results from EMIT were very close to those from HPLC, whereas results from RIA Cyclo-Trac and TDx were slightly overestimated (10-20%). Nonspecific methods (TDx polyclonal and nonspecific RIA Cyclo-Trac) measured CsA concentrations 3-4 times higher than those found by HPLC. The cross-reactivity of CsA metabolites in specific immunoassays was estimated from data of patients' samples and spiked samples; an interference of 6% in RIA Cyclo-Trac, 7% in EMIT, and 26% in TDx FPIA was found. The precision coefficient of variation (CV% between laboratory and between assay) of the methods observed in the 1994 EQA cycle was 9.5 for TDx polyclonal FPIA, 10.4 for TDx monoclonal FPIA, 10.5 for EMIT, 10.6 for RIA specific Cyclo-Trac, 14.2 for RIA nonspecific Cyclo-Trac, and 15.2 for HPLC.
自1987年起，我院组织了一项环孢素（CsA）检测的外部质量评估（EQA）计划，并得到了国家研究委员会（CNR）的支持；1991年，CNR的EQA计划加入了由里昂大学放射药学与放射分析服务部组织的法国CsA实验室间计划。在过去两年（1993年和1994年周期）中，超过170个实验室（来自7个欧洲国家）参与了这项调查，对从心脏和肾脏移植患者的混合血液中制备的44个对照样本进行了检测；还分发了添加了已知量CsA的正常样本库。在整个EQA期间，观察到使用特异性和非同位素技术的趋势。1994年，91%的收集结果是通过特异性方法[高压液相色谱法（HPLC）或为检测未代谢的CsA天然分子而开发的特异性免疫分析方法]得出的；在同一周期中，全自动技术[TDx、荧光偏振免疫分析（FPIA）和酶放大免疫分析（EMIT）]占总结果的73%。通过单克隆特异性免疫分析[TDx FPIA、放射免疫分析（RIA）Cyclo-Trac和EMIT]测量的CsA浓度与HPLC测量的浓度高度相关（r = 0.99 - 1.00）；EMIT的结果与HPLC的结果非常接近，而RIA Cyclo-Trac和TDx的结果略有高估（10 - 20%）。非特异性方法（TDx多克隆和非特异性RIA Cyclo-Trac）测量的CsA浓度比HPLC测量的浓度高3 - 4倍。根据患者样本和加标样本的数据估算了特异性免疫分析中CsA代谢物的交叉反应性；发现RIA Cyclo-Trac的干扰为6%，EMIT为7%，TDx FPIA为26%。在1994年EQA周期中观察到的方法的精密度变异系数（实验室间和分析间的CV%），TDx多克隆FPIA为9.5，TDx单克隆FPIA为10.4，EMIT为10.5，RIA特异性Cyclo-Trac为10.6，RIA非特异性Cyclo-Trac为14.2，HPLC为15.2。
