Skip Navigation



Rheumatology Advance Access published online on October 25, 2006
Rheumatology, doi:10.1093/rheumatology/kel360
This Article
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
46/4/649    most recent
kel360v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Leung, Y. Y.
Right arrow Articles by Kun, E. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Leung, Y. Y.
Right arrow Articles by Kun, E. W.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2006. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
Received August 23, 2006
Accepted September 19, 2006

Original Papers

Urine protein-to-creatinine ratio in an untimed urine collection is a reliable measure of proteinuria in lupus nephritis

Y. Y. Leung 1 *, C. C. Szeto 2, L. S. Tam 2, C. W. K. Lam 3, E. K. Li 2, K. C. Wong 2, S. W. Yu 2, and E. W. Kun 1

1 Department of Medicine and Geriatrics, Tai Po Hosptial, Hong Kong SAR
2 Department of Medicine and Therapeutics, Hong Kong SAR
3 Department of Chemical Pathology, Chinese University of Hong Kong, Hong Kong SAR

* To whom correspondence should be addressed.
Y. Y. Leung, E-mail: katyccc{at}hotmail.com


  Abstract

Objective. To evaluate the accuracy of urine protein-to-creatinine (P/C) ratio in an untimed urine specimen as compared with 24 h total protein excretion for measurement of proteinuria in patients with lupus nephritis.

Methods. Proteinuria in patients with lupus nephritis was assessed by 24 h total protein excretion and spot urine P/C ratio. Correlation and limits of agreement between the two methods were evaluated. The discriminant cutoff values for spot urine P/C ratio in predicting 24 h protein ‘threshold’ excretion of ≥0.3, ≥0.5, ≥1.0 and ≥3.5 g/day were determined using receiver operating characteristic curves.

Results. A total of 165 samples were available for assessment with 21.8% excluded due to inadequate collection. A strong correlation (r = 0.91, P < 0.0001) was found between spot urine P/C ratio and 24 h urine protein excretion. Bland-Altman plot showed the two tests had acceptable limits of agreement in low level of protein excretion (-0.86 to +0.92 g/day when protein excretion was <2.0 g/day). The limits became wider as the protein excretion increased. The spot urine P/C ratios of 0.45 (sensitivity 0.92; specificity 0.88), 0.7 (0.92; 0.89) and 1.84 (1.0; 0.86) mg/mg reliably predicted 24 h urine total protein equivalent ‘thresholds’ at ≥0.5, 1.0 and 3.5 g/day.

Conclusion. This study supports the recommendation of using spot urine P/C ratio in screening and monitoring proteinuria in patients with lupus nephritis. However, in assessing the exact amount of proteinuria, the urine P/C ratio may have unacceptably wide limits of agreement in high protein excretion range.

Keywords: Proteinuria; Urine protein-to-creatinine ratio; Lupus nephritis.
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.