Division of Diabetes Translation, CDC, Atlanta, GA 30333, USA.
Clin Chem. 2013 Apr;59(4):675-83. doi: 10.1373/clinchem.2012.195644. Epub 2013 Jan 11.
Albuminuria, defined as urine albumin/creatinine ratio (ACR) ≥30 mg/g, is a diagnostic component of chronic kidney disease (CKD). National estimates of ACR and CKD prevalence have been based on single random urine samples. Although 2 urine samples or a first morning void are known to produce different estimates of ACR, the impact of differing urine sampling schemes on nationally estimated rates of CKD is unknown.
In 2009-2010, the National Health and Nutrition Examination Survey (NHANES) participants provided 2 untimed urine samples for sequential ACR measurement: an initial random urine collected in the NHANES mobile examination center and a subsequent first morning void collected at home. Rates of albuminuria were calculated in the overall population and broken down by demographics, diagnosed diabetes and hypertension status, and estimated glomerular filtration rate (eGFR).
Overall, 43.5% of adults with increased ACR (≥30 mg/g) in a random urine also had increased ACR in a first morning urine. This percentage was higher among individuals ≥50 years old (48.9%), males (53.3%), participants with diagnosed diabetes (56.3%) and hypertension (51.5%), and eGFR <60 mL/min/1.72m(2) (56.9%). The use of confirmed increased ACR (defined as the presence of ACR ≥30 mg/g in both samples taken within 10 days) to define CKD resulted in a lower overall prevalence (11.6%) than first morning urine (12.7%) or random spot urine only (15.2%).
ACR measured on random urine samples appears to overestimate the prevalence of albuminuria compared to first morning urine collections.
白蛋白尿定义为尿白蛋白/肌酐比值（ACR）≥30mg/g，是慢性肾脏病（CKD）的诊断组成部分。白蛋白尿和 CKD 的国家估计数是基于单次随机尿样得出的。虽然知道两次尿液样本或晨尿可以产生不同的 ACR 估计值，但不同尿液采样方案对全国估计的 CKD 发病率的影响尚不清楚。
在 2009-2010 年，国家健康和营养检查调查（NHANES）参与者提供了 2 份非定时尿液样本，用于连续 ACR 测量：NHANES 移动检查中心采集的初始随机尿液和在家中采集的随后晨尿。在整个人群中计算白蛋白尿的发生率，并按人口统计学、诊断糖尿病和高血压状况以及估计肾小球滤过率（eGFR）进行细分。
总体而言，在随机尿液中 ACR 升高（≥30mg/g）的成年人中，有 43.5%的人在晨尿中也有 ACR 升高。在≥50 岁的个体中（48.9%）、男性（53.3%）、有诊断糖尿病（56.3%）和高血压（51.5%）的个体以及 eGFR<60mL/min/1.72m2（56.9%）中，这一比例更高。使用两次 10 天内采集的样本中均存在 ACR≥30mg/g 的确认性升高 ACR（定义为 ACR 升高）来定义 CKD，其总体患病率（11.6%）低于晨尿（12.7%）或仅随机点尿（15.2%）。
与晨尿收集相比，随机尿样测量的 ACR 似乎高估了白蛋白尿的患病率。
