<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Christopher-Stine, Lisa</style></author><author><style face="normal" font="default" size="100%">Petri, Michelle</style></author><author><style face="normal" font="default" size="100%">Astor, Brad C</style></author><author><style face="normal" font="default" size="100%">Fine, Derek</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Urine protein-to-creatinine ratio is a reliable measure of proteinuria in lupus nephritis.</style></title><secondary-title><style face="normal" font="default" size="100%">The Journal of Rheumatology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004-08-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">1557-1559</style></pages><volume><style face="normal" font="default" size="100%">31</style></volume><issue><style face="normal" font="default" size="100%">8</style></issue><abstract><style  face="normal" font="default" size="100%">OBJECTIVE: To evaluate the 24-hour urine protein-to-creatinine (U pr:cr) ratio compared to 24-h urine total protein excretion as a measure of proteinuria in patients with lupus nephritis. METHODS: Proteinuria in 8 patients with lupus nephritis treated with cyclophosphamide was monitored by total protein excretion and U pr:cr ratio in 24-h urine collections. A median of 16 measurements per patient were collected over a median of 47 months. Adequacy of the 24-h collection was assessed by comparing total urine creatinine to the predicted creatinine. Collections in which the difference between the predicted 24-h urine creatinine and the measured 24-h urine creatinine was greater than or equal to 20% were defined as inadequate collections. RESULTS: Timed 24-h urine collections were frequently inadequate (30.2% of total collections were under-collections, while 14.3% were over-collections). We found 87.5% of patients had at least one under-collection whereas 75% had at least one over-collection. Correlations between total protein and U pr:cr ratio for individual patients ranged from 0.87 to 0.99 (mean 0.95). For the entire sample, the correlation (R2 = 0.89) of total urine protein to Upr:cr ratio was excellent. Excluding the 38 under-collections led to improvement in the overall correlation (0.94). Excluding the 18 over-collections led to a correlation of 0.89. Excluding both under-collections and over-collections led to a correlation of 0.94. CONCLUSION: In patients with lupus nephritis, the 24-h U pr:cr ratio is highly correlated with the 24-h urine protein excretion when the collections are adequate. The error of the estimate is higher when collections are poor.</style></abstract></record></records></xml>