Department of Nephrology and Hypertension, Hospices Civils de Lyon and EA4173: Génomique fonctionnelle de l'HTA Université Claude Bernard Lyon 1, Lyon, France.
Nephron Clin Pract. 2012;122(3-4):80-5. doi: 10.1159/000350429. Epub 2013 Apr 12.
BACKGROUND/AIMS: Urinary albumin excretion is subject to intra-individual variability. Thus, for research purposes, it is recommended to test three urine samples collected over a short period of time. The objective of our analysis was to check the usefulness of triplicate samples to determine the albuminuric status of diabetic patients.
We present the results of the non-planned retrospective analysis of 246 triplicate morning urine samples obtained from 95 type 2 diabetics included in three multinational, randomized, double-blind studies. Albuminuria was determined by immunoturbidimetry on fresh samples in the same central laboratory. Microalbuminuria was defined by a urine albumin to creatinine ratio (UACR) between 2.5 and 25 mg/mmol in males and between 3.5 and 35 mg/mmol in females. Concordance was obtained when the second and/or third sample (UACR2 and UACR3) confirmed the albuminuric status obtained from the first sample (UACR1).
Considering the first samples, 9% were within the normal range, 35% showed microalbuminuria and 56% showed macroalbuminuria. The overall concordance rate was 95%. The log of UACR was highly correlated between samples. Bland-Altman plots expressed in percent variations between two samples confirmed that the mean variation was low (around 8%) but revealed the scattering of values, 95% being between -60 and +77% of variation between samples.
There is no benefit in repeating morning UACR determination in diabetic patients to accurately categorize a subject as having normo-, micro- or macroalbuminuria. However, in order to accurately quantify albuminuria, repeated determinations are required.
背景/目的：尿白蛋白排泄存在个体内变异性。因此，出于研究目的，建议在短时间内检测三个尿液样本。我们分析的目的是检查重复样本是否可用于确定糖尿病患者的蛋白尿状态。
我们呈现了 95 例 2 型糖尿病患者的 246 个早晨重复尿液样本的非计划回顾性分析结果，这些患者被纳入三项多中心、随机、双盲研究。在同一中心实验室使用免疫比浊法在新鲜样本中测定白蛋白尿。微量白蛋白尿定义为男性尿白蛋白与肌酐比值（UACR）在 2.5 至 25mg/mmol 之间，女性在 3.5 至 35mg/mmol 之间。当第二和/或第三份样本（UACR2 和 UACR3）证实了第一份样本（UACR1）的白蛋白尿状态时，即可获得一致性。
考虑到第一份样本，9%处于正常范围内，35%显示微量白蛋白尿，56%显示大量白蛋白尿。总体一致性率为 95%。样本之间的 UACR 对数高度相关。以百分比表示的两个样本之间的 Bland-Altman 图证实了均值变化较小（约 8%），但显示了值的分散，95%的变化值在样本之间的-60%至+77%之间。
对于糖尿病患者，重复测定早晨 UACR 以准确分类为正常、微量或大量白蛋白尿并无益处。然而，为了准确定量白蛋白尿，需要重复测定。
