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| Year : 2010 | Volume
: 21
| Issue : 5 | Page : 949-950 |
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| Protein-to-creatinine ratio: A valid estimate and alternative to 24 hour proteinuria |
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Ayman Karkar, Mohammed Abdelrahman
Department of Nephrology, Kanoo Kidney Centre, Dammam Medical Complex, P.O. Box 11825, Dammam 31463, Saudi Arabia
Click here for correspondence address and email
| Date of Web Publication | 31-Aug-2010 |
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How to cite this article:
Karkar A, Abdelrahman M. Protein-to-creatinine ratio: A valid estimate and alternative to 24 hour proteinuria. Saudi J Kidney Dis Transpl 2010;21:949-50 |
How to cite this URL:
Karkar A, Abdelrahman M. Protein-to-creatinine ratio: A valid estimate and alternative to 24 hour proteinuria. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2020 Oct 21];21:949-50. Available from: https://www.sjkdt.org/text.asp?2010/21/5/949/68900 |
To the Editor,
The 24 hour urine collection test has been the gold standard method of assessing urinary protein excretion in patients with nephrotic syndrome and chronic kidney disease. It is used extensively for diagnostic and prognostic purposes and to assess the effects of therapy. This test is usually performed in a hospital laboratory and requires clear instructions to patients or their companions and supplementation of patients with a graduated plastic container. However, there are limitations to the performance of this test. These include (1) the amount of protein excretion is a function of urine volume; (2) adequate collection must be ensured; (3) it is cumbersome for patients and not many of them clearly understand or stick to the given instructions; (4) it is time consuming and not always accurate; (5) lack of its availability in health centers and occasionally in hospital laboratories and (6) may constitute a huge burden on laboratories workload. In 1983 Ginsberg et al [1] established a quick test of single voided urine sample to estimate quantitative proteinuria. In a study of 46 specimens they found an excellent correlation between the protein content of 24hour 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. They concluded that 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. This protein/creatinine ratio test on random urine samples has been recommended by the National Kidney Foundation-K/DOQI guide lines. [2]
In our daily practice, we faced the above mentioned difficulties in assessing proteinuria by 24-hour urine collection. These reasons and the need to repeat measurements for a successful clinical management prompted us to evaluate the reliability of the urine protein/creatinine ratio as a replacement of the 24-hour urine collection for measurement of proteinuria. We investigated 150 patients with proteinuria due to variable causes of chronic kidney disease including diabetic nephropathy, glomerulonephritis and nephrotic syndrome who were on regular follow up in outpatient nephrology clinic. Only 116 patients (77%) were able to fulfill the instructions of urine collection. The mean age of these patients was 52 ± 13 years and there were 60 males and 56 females. Patients were requested to provide 24-hour urine collection and a random morning urine sample for proteinuria and protein/creatinine ratio measurements. The mean daily protein excretion was 2.168 ± 3.089 gm/24 hour and the mean protein/creatinine ratio was 2.171 ± 2.719 mg/mg. There was a strong and significant positive correlation between the 24-hour urine total protein excretion and the spot urine protein/creatinine ratio (r= 0.942, P< 0.0001, MedCalc statistical software version 10.4) as shown in the [Figure 1]. However, there might be a lower agreement between the 24-hour proteinuria and the protein/creatinine ratio for higher levels of proteinuria. In conclusion, these results confirm the early findings of Ginsberg et al 1 and are consistent with similar recently published studies, [3],[4],[5] where random spot urine analysis for protein/creatinine ratio could be a reliable and convenient method that may replace the proteinuria assessment by 24-hour urine collection. | Figure 1 :Scattered diagram of spot urine protein-to-creatinine ratio and 24-hour urine protein
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 References | |  |
| 1. | Ginsberg JM, Chang BS, Matarese RA, Garella S. Use of single voided urine samples to estimate quantitative proteinuria. N Engl J Med 1983; 309:1543-6.  [PUBMED] [FULLTEXT] |
| 2. | Keane WF, Eknoyan G. Proteinuria, albuminuria, risk, assessment, detection, elimination (PARADE): A position paper of the National Kidney Foundation. Am J Kidney Dis 1999;33:1004-10. [PUBMED] [FULLTEXT] |
| 3. | Wahbeh AM, Ewais MH, Elsharif ME. Comparison of 24-hour urinary protein and proteinto-creatinine ratio in the assessment of proteinuria. Saudi J Kidney Dis Transpl 2009;20(3): 443-7. |
| 4. | Antunes VV, Veronese FJ, Morales JV. Diagnostic accuracy of the protein/creatinine ratio in urine samples to estimate 24-H proteinuria in patients with primary glomerulopathies: a longitudinal study. Nephrol Dial Transplant 2008;23: 2242-6. [PUBMED] [FULLTEXT] |
| 5. | Rodriguez-Thompson D, Lieberman ES. Use of a random urinary protein-to-creatinine ratio for the diagnosis of significant proteinuria during pregnancy. Am J Obstet Gynecol 2001;185:80811. [PUBMED] [FULLTEXT] |
Correspondence Address:
Ayman Karkar
Department of Nephrology, Kanoo Kidney Centre, Dammam Medical Complex, P.O. Box 11825, Dammam 31463
Saudi Arabia
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PMID: 20814140 
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