Variability of Creatinine Measurements in Clinical Laboratories: Results from the CRIC Study
Variability of Creatinine Measurements in Clinical Laboratories: Results from the CRIC Study
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DOI：
10.1159/000296250
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发表时间：
2010-01-01
影响因子：
4.2
通讯作者：
Hamm, L. Lee
中科院分区：
文献类型：
--
作者：
Joffe, Marshall;Hsu, Chi-Yuan;Hamm, L. Lee
目的用血清肌酐（SCr）估算方程常用于评估肾小球滤过率（GFR）。这种基于肌酐（Cr）的公式在使用未校准到参考实验室的Cr测量值时可能产生GFR的偏差估计。在本文中，我们试图在与慢性肾功能不全队列（CRIC）研究相关的学术医学中心的几个实验室中检查Cr测定中这种差异的程度；考虑如何最好地纠正这种变化，并量化这种纠正对参与CRIC资格的影响。crc是一项针对慢性肾脏疾病患者的大型多中心研究，在进行crc时，Cr的可变性尤其值得关注，因为该研究的资格取决于基于Cr的GFR评估。方法收集5份大容量血浆标本，分别代表血浆Cr 0.8 ~ 2.4 mg/dl。该文库中的样品用于在14个CRIC实验室中随时间重复测量Cr。我们使用图形显示和线性回归方法来检验Cr的变异性，并使用线性回归来建立校准方程。我们还检查了各种校准方程对筛选为实际符合研究条件的潜在参与者的受试者比例的影响。结果在不同的实验室和不同的时间，铬的测定结果有很大的差异。我们为每个实验室制定了校准方程；这些方程式在不同的实验室之间有很大的不同，在一些实验室中随着时间的推移也有一些不同。实验室地点对变异的贡献最大（标本无法解释的变异占51%），随时间的变化占另外15%。在一些实验室中，校准方程导致crc合格性差异高达20%。结论：不同实验室的SCr测定方法存在很大差异，因此需要将SCr测量方法校准到一个共同的标准。如果不这样做，可能会严重影响研究资格和临床解释，当它们由基于cr的GFR估计确定时。
ObjectivesEstimating equations using serum creatinine (SCr) are often used to assess glomerular filtration rate (GFR). Such creatinine (Cr)-based formulae may produce biased estimates of GFR when using Cr measurements that have not been calibrated to reference laboratories. In this paper, we sought to examine the degree of this variation in Cr assays in several laboratories associated with academic medical centers affiliated with the Chronic Renal Insufficiency Cohort (CRIC) Study; to consider how best to correct for this variation, and to quantify the impact of such corrections on eligibility for participation in CRIC. Variability of Cr is of particular concern in the conduct of CRIC, a large multicenter study of subjects with chronic renal disease, because eligibility for the study depends on Cr-based assessment of GFR.MethodsA library of 5 large volume plasma specimens from apheresis patients was assembled, representing levels of plasma Cr from 0.8 to 2.4 mg/dl. Samples from this library were used for measurement of Cr at each of the 14 CRIC laboratories repetitively over time. We used graphical displays and linear regression methods to examine the variability in Cr, and used linear regression to develop calibration equations. We also examined the impact of the various calibration equations on the proportion of subjects screened as potential participants who were actually eligible for the study.ResultsThere was substantial variability in Cr assays across laboratories and over time. We developed calibration equations for each laboratory; these equations varied substantially among laboratories and somewhat over time in some laboratories. The laboratory site contributed the most to variability (51% of the variance unexplained by the specimen) and variation with time accounted for another 15%. In some laboratories, calibration equations resulted in differences in eligibility for CRIC of as much as 20%.ConclusionsThe substantial variability in SCr assays across laboratories necessitates calibration of SCr measures to a common standard. Failing to do so may substantially affect study eligibility and clinical interpretations when they are determined by Cr-based estimates of GFR.