血浆Septin9基因甲基化检测质控品制备及其应用

目的制备可模拟临床标本的血浆Septin9基因甲基化(mSEPT9)质控品并用于室间质量评价。方法选择Septin9区域已发生/未发生甲基化的HeLa/Jurkat细胞进行培养,收集并抽提细胞基因组DNA,经mSEPT9试剂盒检测,依据检测Ct值用阴性血浆稀释分装成含有不同浓度的质控品,对质控品均匀性和稳定性进行评价后,将5个样品随机编号后发送至参评实验室,分析评价回报结果。结果抽提得到的细胞基因组DNA纯度和浓度均可满足使用需求,且可用作mSEPT9检测的质控品。均匀性和稳定性均符合中国合格评定国家认可委员会对能力验证样品要求。部分参评实验室出现假阳性和假阴性情况,仅有约55.6%实验室的检测结果(Ct值)呈良好线性相关。9家参评实验室中,7家实验室(77.8%)成绩优秀,1家实验室(11.1%)成绩合格,1家实验室(11.1%)成绩不合格。结论成功研制血浆mSEPT9检测的质控品并应用于室间质评,有利于评估并提升临床实验室检测能力。

Development and application of quality control materials for detection of methylated Septin9 DNA in plasma

Objective To develop a kind of quality control material which simulates clinical specimens for detecting plasma methylated Septin9(mSEPT9) and investigate the performance for mSEPT9 detection in external quality assessment(EQA) of laboratories. Methods The cultured Hela and Jurkat cells, known to contain methylated and unmethylated Septin9 gene respectively, were cultured. The genomic DNA of the cells was collected and extracted, and detected by mSEPT9 kit. According to the Ct value, the genomic DNA was diluted into different concentrations of quality control materials with negative plasma. The homogeneity and stability of the quality control materials were evaluated. The panels consisted of 5 blindly coded samples were distributed to EQA participants and the results were summarized and evaluated. Results The purity and concentration of extracted genomic DNA met with the needs of use and could be used as quality control products for mSEPT9 detection. The homogeneity and stability met with the requirements of China National Accreditation Service for Conformity Assessment. Some of the participating laboratories occurred false positive results and false negative results, and a good linear correlation for the detected results(Ct values) was only observed in about 55.6% of the laboratories. Among the 9 participating laboratories, 7 laboratories(77.8%) performed well, 1 laboratory(11.1%) qualified, and 1 laboratory(11.1%) unqualified. Conclusion The quality control materials for mSEPT9 detection was successfully developed and the application in external quality assessment should be of great significance for evaluating and improving the detection ability of clinical laboratory.