Urine protein/creatinine ratio explained

Urine protein/creatinine ratio is a widely used initial method to estimate daily protein excretion in urine.^{[1] [2] [3]} Since the diagnosis and management of proteinuric renal diseases and the staging of chronic kidney disease depend on accurate identification and quantitation of proteinuria,^[1] the implementation of the 24-hour urine collection is the most accurate procedure in practice to figure out the urinary protein excretion.^[1] However, in current clinical practice, the urine protein/creatinine ratio is widely used to estimate daily protein excretion by virtue of its convenience and simplicity.^{[4] [1]}

The difference between urine protein/creatinine ratio and 24-hour urine collection is that the former requires a urine sample to be collected only once at any time.^[5] [Creatinine(U)] is taken into account due to the notion that creatinine is normally released into the urine at a constant rate.^[5] Scientists found that the ratio of protein to creatinine roughly estimates the actual value gained from the 24-hour urine protein test.^[5] The normal urine protein/creatinine ratio is less than 200 mg/g.^[6]

Notes and References

1. Yang . Chih-Yu . Chen . Fu-An . Chen . Chun-Fan . Liu . Wen-Sheng . Shih . Chia-Jen . Ou . Shuo-Ming . Yang . Wu-Chang . Lin . Chih-Ching . Yang . An-Hang . Kim . Jayoung . Diagnostic Accuracy of Urine Protein/Creatinine Ratio Is Influenced by Urine Concentration . PLOS ONE . Public Library of Science (PLoS) . 10 . 9 . 2015-09-09 . 1932-6203 . 26353117 . 4564100 . 10.1371/journal.pone.0137460 . e0137460 . 2015PLoSO..1037460Y . free .
2. Web site: Protein urine test: MedlinePlus Medical Encyclopedia . MedlinePlus . 2019-05-08 . 2019-05-21.
3. Web site: Protein in Urine: MedlinePlus Lab Test Information . MedlinePlus . 2019-04-15 . 2019-05-21.
4. Ginsberg . Jay M. . Chang . Bruce S. . Matarese . Richard A. . Garella . Serafino . Use of Single Voided Urine Samples to Estimate Quantitative Proteinuria . The New England Journal of Medicine . Massachusetts Medical Society . 309 . 25 . 1983-12-22 . 0028-4793 . 6656849 . 10.1056/nejm198312223092503 . 1543–1546.
5. Web site: Urine Protein . Lab Tests Online . 2019-05-21.
6. Summary of Recommendation Statements . Kidney International Supplements . Elsevier BV . 3 . 1 . 2013 . 2157-1716 . 25598998 . 4284512 . 10.1038/kisup.2012.77 . 5–14.