The Relationship Between Random Urinary Protein-To-Creatinine Ratio and 24-Hours Urine Protein in Diagnosis of Proteinuria in Mild Preeclampsia



Taherian AA¹ ; Dehbashi S² ; Baghban M¹
Source: Journal of Research in Medical Sciences Published:2006

Abstract

Background: The purpose of this study was to evaluate whether a random urinary protein/creatinine ratio is a clinically useful predictor of significant proteinuria (≥300 mg/24 hr) instead of 24- hours urine protein, among women with suspected preeclampsia. Methods: Women with suspected preeclampsia and gestational age of ≥20 weeks were included in a prospective study. Patients with chronic hypertension, diabetes mellitus, or preexisting renal disease were excluded. Protein/creatinine ratio was obtained before 24-hours urine collection. Positive and negative predictive values and sensitivity and specificity of the protein/creatinine ratio for significant proteinuria (≥ 300 mg) were calculated, based on 24-hours urine total protein. Results: 100 women were evaluated totally. Mean maternal and gestational ages were 27.3 years and 33.26 weeks, respectively. 73% of cases had significant proteinuria based on 24-hours urine collection. Good correlations were found between the protein/creatinine ratio in random urine samples and both the 24-hours urine protein excretion and the 24-hours urine protein/creatinine ratio in patients with mild preeclampsia (r=0.484, P<0.0001, and r=0.345, P<0.0001, respectively). Receiver operator characteristic (ROC) analysis revealed an area under the curve of 0.944. The best cutoff value was of >0.18 which yields a sensitivity of 86.3%, a specificity of 100%, with a positive predictive value of 100%, and a negative predictive value of 73%. Conclusion: The random urinary protein -to- creatinine (P: C) ratio is strongly associated with the 24-hours total protein excretion. A cutoff value of > 0.18 is a good predictor of significant proteinuria P: C ratio could replace the 24-hours urine collection as a simpler, faster, and more accurate method for the diagnosis of significant proteinuria.