Ginsberg J M, Chang B S, Matarese R A, Garella S
N Engl J Med. 1983 Dec 22;309(25):1543-6. doi: 10.1056/NEJM198312223092503.
Quantitation of urinary protein excretion is used extensively for diagnostic and prognostic purposes and to assess the effects of therapy. The method most commonly used to measure urinary protein relies on 24-hour urine collections, which are time consuming, cumbersome, and often inaccurate. We reasoned that the urinary protein/creatinine ratio in a single voided urine sample should correlate well with the quantity of protein in timed urine collections. In a study of 46 specimens we found an excellent correlation between the protein content of a 24-hour urine collection and the protein/creatinine ratio in a single urine sample. The best correlation was found when samples were collected after the first voided morning specimen and before bedtime. We conclude that the determination of the protein/creatinine ratio in single urine samples obtained during normal daylight activity, when properly interpreted by taking into consideration the effect of different rates of creatinine excretion, can replace the 24-hour urine collection in the clinical quantitation of proteinuria. In the presence of stable renal function, a protein/creatinine ratio of more than 3.5 (mg/mg) can be taken to represent "nephrotic-range" proteinuria, and a ratio of less than 0.2 is within normal limits.
尿蛋白排泄定量广泛用于诊断和预后评估以及评估治疗效果。最常用于测量尿蛋白的方法依赖于收集24小时尿液，这种方法既耗时、麻烦，而且常常不准确。我们推断单次随机尿样中的尿蛋白/肌酐比值应与定时尿样中的蛋白量具有良好的相关性。在对46份标本的研究中，我们发现24小时尿样中的蛋白含量与单次尿样中的蛋白/肌酐比值之间具有极佳的相关性。当样本在早晨首次排尿后的标本采集且在睡前采集时，相关性最佳。我们得出结论，在正常日间活动期间采集的单次尿样中测定蛋白/肌酐比值，在适当考虑肌酐排泄率不同的影响进行解释时，可替代24小时尿样用于临床蛋白尿定量。在肾功能稳定的情况下，蛋白/肌酐比值大于3.5（mg/mg）可被视为“肾病范围”蛋白尿，而比值小于0.2则在正常范围内。
