顺磁性微粒子化学发光免疫分析法检测血清叶酸的性能评价

Performance of paramagnetic chemiluminescence microparticle immunoassay for determination of serum folic acid

目的：评估顺磁性微粒子化学发光免疫分析法（chemiluminescence microparticle immunoassay,CMIA）检测血清叶酸的分析性能,证实其是否能满足实验室需求。方法：应用美国临床和实验室标准化协会（CLSI）EP5-A2、EP15-A2、EP7-A2、EP6-A、C28-A3c方法评价CMIA检测叶酸的精密度、正确度、抗干扰性、分析测量范围（AMR）、临床可报告范围（CRR）、生物参考区间及叶酸样本在不同温度、光照条件下的稳定性。结果：叶酸浓度在2.68-28.17 nmol·L^-1时,批内、批间精密度均小于厂家声明的标准。正确度验证显示测定有证参考物质NIST SRM 1955,结果符合验证要求;检测美国病理学家协会室间质评物（K-C）、校准验证/线性评价物（LN5-B）显示,结果均符合美国病理学家协会校准验证/线性评价误差界限所规定的标准,叶酸浓度在1.26-30.83 nmol·L^-1范围内通过线性验证,95%验证区间也包含其指定均值,相对偏差均小于卫生部临床检验中心室间质量评价标准（TEa：靶值±30%）,但结果整体水平偏低,尤其低水平明显,最大相对偏差达-28.44%。抗干扰性评估显示在甘油三脂（TG）浓度≤20 mmol·L^-1、胆红素（Bil）浓度≤400μmol·L^-1、维生素C质量浓度≤2.0 g·L^-1时对叶酸检测系统CMIA无显著干扰。AMR验证判断最佳拟合方程为二元一次多项式,叶酸浓度在0-45.31 nmol·L^-1范围内存在线性关系。CRR上限为6796.5 nmol·L^-1,最大稀释倍数为150倍。生物参考区间验证显示本研究选择的参考个体叶酸总体水平低于美国人群叶酸水平,男性叶酸水平低于女性叶酸水平。温度、光照的稳定性试验提示血清叶酸标本常温保存不宜超过2 d。结论：CMIA检测血清叶酸的各项性能指标基本满足实验室要求。样本密封、避光和低温保存稳定性较好。实验室需结合地区饮食差异,建立或验证生物参考区间。

Objective：To evaluate the performance of paramagnetic chemiluminescence microparticle immunoassay （CMIA） for serum folie acid. Methods ： Performance verification tests for precision, accuracy, anti - interference, analytical measuring range （AMR）,clinical reportable range （CRR）, biological reference interval and stability at different temperatures and illumination conditions were conducted according to the clinical and laboratory standards institute （CLSI） EP5 - A2, EP15 - A2, EP7 - A2, EP6 - A, C28 - A3c guidelines. Results ： The precisions of with- in - run and between - run were lower than the stated specification by manufacturers when the concentration of folic acid was 2.68 -28.17 nmol· L^-1. The accuracy test results of SRM 1955 met the allowable range of the target val- ue. The results of EQA samples （ K - C and LN5 - B） also met the CAP calibration and validation/linear evaluation error limits standards, and met linear verification when folie acid concentration was from 1.26 to 30. 83 nmol · L^-1 The 95 % verification interval also contained the assigned value. The relative deviation was less than the standard of external quality assessment by national center for clinical laboratory （ TEa ： target value ± 30% ）. However. The overall results were relatively low, especially for the low level and the maximum relative deviation was up to -28.44%. Anti - interference showed that the triglyceride （TG） concentration ≤ 20 mmol · L^-1 bilirubin （Bil） concentration≤ 400 μmol · L^-1,and vitamin C mass concentrations〈2 g · L^-1 had no significant interference on the folic acid detection system （CMIA）. AMR validation showed that the best fit equation was linear equation polynomial. There was linear relationship when the concentration of folic acid was 0 -45.31 nmol · L^-1. The upper limit of CRR was 6796.5 nmol · L^-1. and the maximum dilution was 150 times. Reference interval validation showed that the overall level of folic acid in reference individuals were lower than that in Americans. The levels of folic acid in males were lower than those in females. Serum folic acid should not be stored more than 2 clays at normal temperatures. Conclusion：Performance of CMIA for detection of serum folic acid met laboratory requirements. Stability was better when samples were stored sealed, away from light and at low temperatures. The laboratory should establish or verify the reference interval according to regional dietary differences.