Background Urine albumin (UA) is an important biomarker of chronic kidney disease. Current in vitro diagnostic medical devices (IVD-MDs) for measuring UA are not standardized, and median results among IVD-MDs differ by approximately 45%. Since fixed decision values are used to interpret UA, higher-order reference measurement procedures (RMPs) are needed for metrological traceability. Three candidate liquid chromatography-tandem mass spectrometry RMPs have been developed for UA. Methods Eight single-donation human urine samples were measured by 3 candidate RMPs. Results were compared using t-test and variance component analysis. Results The mean results for each urine sample from each RMP laboratory were not statistically different from the overall mean value by t-test. The median total CV including contributions from bias and imprecision among the 3 RMP laboratories was 6.23% using variance component analysis for each sample. The allowable bias to the RMP for an end-user IVD-MD was ≦9.0% or ≦3.0% based on the desirable or optimal total allowable error of 30% or 24%, respectively. A maximum allowable standard uncertainty for an RMP result was determined to be 4.3% or 3.3% for desirable or optimal performance, respectively. The standard uncertainties for all of the RMP laboratories meet the desirable and optimal standard uncertainty specifications. Conclusion The candidate RMPs for UA in these 3 laboratories have suitable agreement of results and uncertainties for use as higher-order RMPs in the metrological traceability of end-user IVD-MDs for measuring UA.

中文翻译：

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3 种候选质谱参考测量程序中尿白蛋白结果的等效程度


背景 尿白蛋白 （UA） 是慢性肾病的重要生物标志物。目前用于测量 UA 的体外诊断医疗器械 （IVD-MD） 尚未标准化，IVD-MD 的中位结果差异约为 45%。由于使用固定判定值来解释 UA，因此需要更高阶参考测量程序 （RMP） 来实现计量溯源。已经为 UA 开发了三种候选液相色谱-串联质谱 RMP。方法 用 3 个候选 RMP 测量 8 个单次捐献的人尿液样本，使用 t 检验和方差分量分析比较结果。结果 各 RMP 实验室每份尿液样本的平均结果与 t 检验的总体平均值无统计学差异。使用每个样本的方差成分分析，3 个 RMP 实验室中包括偏倚和不精确性贡献在内的中位总 CV 为 6.23%。最终用户 IVD-MD 的 RMP 允许偏差分别为 ≦9.0% 或 ≦3.0%，基于 30% 或 24% 的理想或最佳总允许误差。对于理想或最佳性能，RMP 结果的最大允许标准不确定度分别为 4.3% 或 3.3%。所有 RMP 实验室的标准不确定度均满足理想的最佳标准不确定度规格。结论 这 3 个实验室中用于 UA 的候选 RMP 在结果和不确定性方面具有适当的一致性，可用作最终用户 IVD-MD 计量溯源中高阶 RMP，用于测量 UA。