肌氨酸氧化酶法检测尿肌氨酸的方法学性能评价及参考值分析

Urine sarcosine determination using sarcosine oxidase method:evaluation of methodology and assessment of reference value

目的对肌氨酸氧化酶法检测尿肌氨酸进行方法学性能评价,初步估计尿肌氨酸的生物参考值。方法参考CLSI EP5-A2、EP17-A、EP6-A、C28-A3等文件,评价肌氨酸氧化酶法检测尿肌氨酸的重复性、空白限(limits of blank,LoB)、检测限(limitsof detection,LoD)、定量限(limits of quantitation,LoQ)、线性范围、回收率和生物参考值。结果肌氨酸氧化酶法检测2.0μmol/L肌氨酸溶液、2.9μmol/L新鲜尿液样本,总不精密度均<14.0%;肌氨酸氧化酶法检测5.0、10.0μmol/L肌氨酸溶液及6.4、9.8μmol/L新鲜尿液样本,总不精密度均<10.0%。肌氨酸氧化酶法检测尿肌氨酸的LoB约为0.35μmol/L;肌氨酸溶液的LoD、LoQ分别为1.1、1.9μmol/L,新鲜尿样本分别为1.2、2.0μmol/L;线性范围为2.0～125.6μmol/L;回收率为65.3%～90.5%。健康人群尿肌氨酸的生物参考值为0.01～0.06μmol/g肌酐。结论肌氨酸氧化酶方法检测尿肌氨酸的精密度、检测限、线性范围等可满足临床实验室的要求,但仍需在校准品基质方面有所改进以提高准确度。

Objective To evaluate the performance of sarcosine oxidase methods in the determination of urine sarcosine level and establish the biological reference range of urine sarcosine. Methods According to the documents CLSI EP5-A2, EP17-A, EPC6-A and C28-A3, the reproducibility, limit of blank （LOB）, limit of detection （LoD）, limit of quantitation （LoQ）, linear range, recovery rate and biological reference value of the sarcosine oxidase method for determination of urine sarcosine level were evaluated. Results In the determinations for the target solution of sarcosine of 2.0 μmol/L and the fresh urine specimen with sarcosine of 2.9 μmol/L the total imprecision of the sarcosine oxidase method was less than 14.0%, while the total imprecision was less than 10.0% in the determinations for sarcosine solution of 5.0 μmol/L and 10.0 μmol/L, or fresh urine specimen with sarcosine of 6.4 μmol/L and 9.8 μmol/L. The LoB was about 0.35 μmol/L. The LOD for sarcosine solution and fresh urine specimen were 1. 1 μmol/L and 1.2 μmoL/L respectively. The LoQ for sarcosine solution and urine specimen were 1.9 μmol/L and 2.0 Ixmol/L respectively. The linear range was from 2.0 to 125.6 μmol/L, and the recovery rate was from 65.3% to 90.5%. The reference value of urine sarcosine level in healthy crowd was from 0.01 to 0. 06 μmol/g creatinine without difference in age and gender. Conclusion The precision, limits of detection and linear range of sarcosine oxidase method for detecting urine sarcosine level can meet the requirements of clinical laboratory, but the calibrator matrix should be modified to improve the accuracy of the assay.