Selvarajah Viknesh, Flynn Robert, Isles Chris
Renal Unit, Dumfries and Galloway Royal Infirmary, Dumfries, University of Dundee, Ninewells Hospital & Medical School, Dundee, UK.
Nephron Extra. 2011 Jan;1(1):235-41. doi: 10.1159/000333474. Epub 2011 Dec 21.
Current UK guidelines for the identification, management and referral of chronic kidney disease advise an early-morning urine sample for the albumin:creatinine ratio or the protein:creatinine ratio (PCR) in order to quantify proteinuria. Estimated protein output (EPO) is an alternative and possibly better method of quantifying proteinuria which takes lean weight into consideration.
We carried out a single-centre study of 36 adult patients with proteinuric nephropathy over a period of 18 months. Urinary PCR and EPO estimates of 24-hour urine protein were compared with 24-hour urine collections by Bland-Altman analysis.
Average 24-hour urine protein was 1.6 g (range 0.2-5.1 g). Best agreement with 24-hour protein was for first-void EPO (limits of agreement 0.33-1.59) followed by a second-void EPO (0.40-1.76), then second-void PCR (0.40-2.08) and lastly first-void PCR (0.28-2.03). None of the differences between estimates of urine protein excretion and 24-hour urine protein were statistically significant. All estimates of protein output had wide confidence intervals confirming that spot urine samples, while simple and convenient to do, are imprecise measures of 24-hour urine protein excretion.
When estimating 24-hour urine protein from a spot urine sample, EPO may be marginally more accurate than PCR, and first-void urine samples slightly better than second-void urine samples, but a first- or second-void PCR will suffice in most instances.
英国目前关于慢性肾病的识别、管理及转诊的指南建议，采用清晨尿样检测白蛋白与肌酐比值或蛋白与肌酐比值（PCR），以量化蛋白尿。估计蛋白排出量（EPO）是另一种量化蛋白尿的方法，可能更好，因为它考虑了瘦体重。
我们对36例成年蛋白尿性肾病患者进行了为期18个月的单中心研究。通过Bland-Altman分析，将尿PCR和24小时尿蛋白的EPO估计值与24小时尿收集量进行比较。
24小时尿蛋白平均为1.6g（范围0.2 - 5.1g）。与24小时蛋白一致性最好的是首次排尿EPO（一致性界限为0.33 - 1.59），其次是第二次排尿EPO（0.40 - 1.76），然后是第二次排尿PCR（0.40 - 2.08），最后是首次排尿PCR（0.28 - 2.03）。尿蛋白排泄估计值与24小时尿蛋白之间的差异均无统计学意义。所有蛋白排出量的估计值都有较宽的置信区间，证实即时尿样虽然操作简单方便，但对24小时尿蛋白排泄的测量并不精确。
从即时尿样估计24小时尿蛋白时，EPO可能比PCR略准确，首次排尿尿样略优于第二次排尿尿样，但在大多数情况下，首次或第二次排尿PCR就足够了。
