胱抑素C国家标准物质的研制

Establishment of first national standard of Cystatin C

目的 研制胱抑素C标准物质.方法 前瞻性研究.以重组人胱抑素C抗原为原料进行稀释、无菌分装制得；在全自动生化分析仪上完成均匀性和稳定性测试；由6家实验室在严格规定的试验条件下,采用经广泛认可的免疫比浊分析法,与国际标物ERM-DA471进行比较,得到所研制标物的量值；按照文件EP14《基质效应的评价》测试该候选标物及其生理盐水稀释液的互换性.采用Excel 2007软件分析数据.结果 候选标物具有较好的免疫活性,均匀性和稳定性良好,2～8℃密封保存可稳定6个月,常温和37℃密封保存可稳定30 d,开瓶后2～8℃冷藏可稳定30 d,最终定值结果为（4.47 ±0.25） mg/L（包含因子k=2）,该候选标物或其生理盐水稀释液在所评估的10个常规测试系统上具有互换性.结论 该标准物质符合国家二级标准物质要求,可用于该项目的质量评价和控制.

Objective To establish the first national standard of Cystatin C. Methods The candidate standard was prepared from human recombinant Cystatin C, diluted and dispensed aseptically. Homogeneity and stability study were carried out on the automated biochemical analyzer. The target value was assigned by six laboratories using widely recognized immumoassay under strict conditions, and traceable to ERM-DA471. Commutabilities of the candidate standard and its saline dilutions were evaluated according to EP14-Evaluation of Matrix Effects. Excel 2007 was used to analyze the results. Results The preparation had good immunological activity and was proved to be homogeneous and stable （6 months sealed at 2 - 8 ℃, 30 days sealed at room temperature and 37 ℃, 30 days open-vial at 2 - 8 ℃ ）. The assigned value of the preparation was （ 4.47 ± 0. 25 ） mg/L （ coverage factor k = 2 ）. The candidate standard and/or its saline dilutions have commutability on the 10 evaluated systems. Conclusion The preparation meets the requirements of national secondary standard and could be used in quality control and evaluation of Cystatin C assays in China.