D Rodriguez-Thompson1, E S Lieberman. 1. Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA. drodriguez89@post.harvard.edu
Abstract
OBJECTIVE: The purpose of this study was to evaluate whether a random urinary protein-to-creatinine ratio is a clinically useful predictor of significant proteinuria (300 mg/24 hour). STUDY DESIGN: The medical records of 138 women who completed both a random urinary protein-to-creatinine ratio and a 24-hour urine collection for the evaluation of preeclampsia were reviewed. Urine samples for the random protein-to-creatinine ratio were collected before the 24-hour urine collection. With the use of a protein level of at least 300 mg in the 24-hour urine sample as the gold standard, the sensitivity and specificity of the random protein-to-creatinine ratio for the diagnosis of significant proteinuria were determined with a range of cutoffs. RESULTS: Fifty percent of the study population had significant proteinuria. The data suggest that a cutoff below 0.14 ruled out significant proteinuria. The best cutoff of > or = 0.19 yields a sensitivity of 90% and a specificity of 70%. All of the false-negative test results had 24-hour urine protein levels below 400 mg; 13 of the 21 false-positive results had levels that ranged from 250 to 300 mg. CONCLUSION: The random urinary protein-to-creatinine ratio is strongly associated with the 24-hour total protein excretion. A level below 0.14 can rule out significant proteinuria. A best cutoff of > or = 0.19 is a good predictor of significant proteinuria. With further study, the random urinary protein-to-creatinine ratio could replace the 24-hour urine collection as a simpler, faster, more useful method for the diagnosis of significant proteinuria.
OBJECTIVE: The purpose of this study was to evaluate whether a random urinary protein-to-creatinine ratio is a clinically useful predictor of significant proteinuria (300 mg/24 hour). STUDY DESIGN: The medical records of 138 women who completed both a random urinary protein-to-creatinine ratio and a 24-hour urine collection for the evaluation of preeclampsia were reviewed. Urine samples for the random protein-to-creatinine ratio were collected before the 24-hour urine collection. With the use of a protein level of at least 300 mg in the 24-hour urine sample as the gold standard, the sensitivity and specificity of the random protein-to-creatinine ratio for the diagnosis of significant proteinuria were determined with a range of cutoffs. RESULTS: Fifty percent of the study population had significant proteinuria. The data suggest that a cutoff below 0.14 ruled out significant proteinuria. The best cutoff of > or = 0.19 yields a sensitivity of 90% and a specificity of 70%. All of the false-negative test results had 24-hour urine protein levels below 400 mg; 13 of the 21 false-positive results had levels that ranged from 250 to 300 mg. CONCLUSION: The random urinary protein-to-creatinine ratio is strongly associated with the 24-hour total protein excretion. A level below 0.14 can rule out significant proteinuria. A best cutoff of > or = 0.19 is a good predictor of significant proteinuria. With further study, the random urinary protein-to-creatinine ratio could replace the 24-hour urine collection as a simpler, faster, more useful method for the diagnosis of significant proteinuria.
Authors: Irina A Buhimschi; Guomao Zhao; Edmund F Funai; Nathan Harris; Isaac E Sasson; Ira M Bernstein; George R Saade; Catalin S Buhimschi Journal: Am J Obstet Gynecol Date: 2008-11 Impact factor: 8.661