校准方式与CK和LDH检测结果一致性

Calibration mode and harmonization of CK and LDH results

目的应用酶学参考方法实验室网络赋值的人源冰冻血清做校准品，探求实现不同检测系统间检测结果一致性的途径，为实验室确定适合的项目校准方式提供参考方法。方法量值溯源研究。由首都医科大学附属北京朝阳医院、北京航天总医院、首都医科大学附属北京世纪坛医院、中国医学科学院北京协和医院、北京利德曼生化股份有限公司、四川迈克生物科技股份有限公司6家实验室组成的酶学参考方法实验室网络使用国际临床化学和检验医学联合会（IFCC）推荐的磷酸肌酸激酶（CK）、乳酸脱氢酶（LDH）参考测量程序为新鲜冰冻混合人血清赋值，再用此赋值血清做统一的酶校准品，于2012年2月校准8套北京地区的单点校准模式的常规检测系统。每日校准程序校准各系统后顺序检测定值血清、原系统厂家校准品、质控品和患者样本；患者样本为北京市临床检验中心于2011年9月至11月收集的中国医学科学院阜外心血管病医院患者验后血清样本。再固定10日平均校准系数（以下简称：固定K均值）。并用它替换每日校准系数，以固定K均值重新计算获得上述相应的结果，比较两者的室内精密度。计算患者样本校准前、后的均值、标准差、变异系数（CV）以及原系统校准品的偏移等统计学指标。结果定值血清校准后，8台常规检测系统原系统校准品赋值的偏移有不同，CK、LDH各有2个校准品赋值偏移〉5％；患者样本CK结果系统问CV分别由3．78％和4．44％下降到0．74％和0．89％；LDH由4．11％和4．08％下降到1．08％和1．28％。每日校准与固定K均值两种校准方式比较结果显示：CK项目K值的CVs≤1．00％、LDH项目CVs≤2．50％的检测系统，各样本的系统内CVs分别小于1．50％和3．00％；且两种校准方式原系统校准品、质控品及患者样本的CV均没有明显差异；而对于CK项目K值CV〉1．00％、LDH项目CV〉2．50％的系统，系统内CV明显增大；并有系统显示，各样本固定K均值的CV较每日校准的CV明显增大。结论使用参考方法实验室网络赋值的冰冻人源血清做统一的酶校准品，校准不同的单点校准模式的开放检测系统，可实现CK、LDH检测结果的一致性，并使结果溯源至参考方法。实验室应基于检测系统的稳定性确定适宜的校准方式。

Objective Using the frozen hmnan-pooled serum samples assigned by the enzymology reference procedure laboratory network as the calibrator, to find the way for harmonizing results among different measurement systems of enzymology, and providing a reference method for clinical laboratory to determine the appropriate calibration mode. Methods The study is about quantity traceability. Using the frozen human-pooled serum sample assigned by the enzymology reference laboratory network consisted of six domestic reference laboratories, namely Beijing Chaoyang Hospital affiliate of Capital University of Medical Sciences, Beijing Aerospace general Hospital, Beijing Shijitan Hospital affiliate of Capital University of Medical Sciences, Peking Union Medical College Hospital, Beijing Leadman Biochemistry Co. ,ltd, SichuanMaker Biotechnology Co. , hd, using the International Federation of Clinical Chemistry and Laboratory Medicine （IFCC） reference measurement procedures of creatine kinase （CK） and lactate dehydrogenase （LDH） as the same calibrator, to calibrate eight measurement systems with single point calibration mode of routine laboratories In February 2012 in Beijing. The value-assigned human sample, manufacturers＇ calibrators,control materials and the patient samples were detected after each measurement system was calibrated by daily calibration. The patient samples were collected by Beijing Center for Clinical Laboratories between September and November 2011 from Chinese academy of medical sciences Fuwai hospital cardiovascular disease. Then, each results were recalculated with the another procedure which was fixed by average calibration factor of ten days （hereinafter referred to as fixed K）. Then, we had compared statistical results for the two procedures. The statistical indicators of mean, standard deviation, coefficient of variation of the patient samples were calculated before and after calibration and the biases of the original system calibrators were also done. Results After calibration, the biases of eight original detection system calibrators were different, two out of eight were bigger than 5% for both CK and LDH. The coefficients of variation （CVs） of the two patient samples of CK dropped by 3.78% and 3.78% to 4. 44% and 3.78% respectively; LDH dropped by 4. 11% and 4. 11% to 4.08% and 4. 11%. The statistical results of two procedures showed that under the circumstance of the CVs of calibration factor for CK and LDH were not bigger than 1.00% and 2. 50% , the intra-detection system CVs of all the sample results were less than 1.50% and 3.00%. It was no significant difference between the two procedures in CVs of the original system calibration product, control materials and the patient samples. While on the condition that the CVs of calibration factor for CK and LDH were larger than 1.00% and 2. 50% , the intra-detection system CVs increased and the CVs of fixed K of all samples were larger than those of daily calibration. Conclusions Using the frozen human-pooled serum samples assigned by the enzymology reference procedure laboratory network as the calibrator, to calibrator the different measurement system with calibration mode of single point, can realize the consistency of the testing results of CK and LDH, and making the results traceable to the reference measurement procedure. Laboratory should base on the stability of the detection system to determine the appropriate calibration mode.