Use of Protein:Creatinine Ratio Measurements on Random Urine Samples for Prediction of Significant Proteinuria: A Systematic Review

Abstract

Background: Proteinuria is recognized as an independent risk factor for cardiovascular and renal disease and as a predictor of end organ damage. The reference test, a 24-h urine protein estimation, is known to be unreliable. A random urine protein:creatinine ratio has been shown to correlate with a 24-h estimation, but it is not clear whether it can be used to reliably predict the presence of significant proteinuria. Methods: We performed a systematic review of the literature on measurement of the protein:creatinine ratio on a random urine compared with the respective 24-h protein excretion. Likelihood ratios were used to determine the ability of a random urine protein:creatinine ratio to predict the presence or absence of proteinuria. Results: Data were extracted from 16 studies investigating proteinuria in several settings; patient groups studied were primarily those with preeclampsia or renal disease. Sensitivities and specificities for the tests ranged between 69% and 96% and 41% and 97%, respectively, whereas the positive and negative predictive values ranged between 46% and 95% and 45% and 98%, respectively. The positive likelihood ratios ranged between 1.8 and 16.5, and the negative likelihood ratios between 0.06 and 0.35. The cumulative negative likelihood ratio for 10 studies on proteinuria in preeclampsia was 0.14 (95% confidence interval, 0.09 -0.24). Conclusion: The protein:creatinine ratio on a random urine specimen provides evidence to "rule out" the

Predicting proteinuria in hypertensive pregnancies with urinary protein-creatinine or calcium-creatinine ratio

“…17 Our study also stresses the need for more frequent audit of the operational policies of laboratory and obstetric hospital services and for regular update of patient management protocols in resource-constrained settings in the developing world. 5,8 The results clearly showed that spot urinary protein-creatinine in a pre-24 h urine collection sample is predictive of total urinary protein excretion in hospitalized pregnant women with HDP irrespective of the amount of proteinuria or type of hypertension.…”

“…Subjects who have been placed on long-term bed rest at home or strict bed rest in another hospital for more than 36 h before admission were also excluded because of the decreased correlation between the urine protein-creatine ratio and the 24-h urine protein resulting from prolonged recumbency. 2,6,8,16,17 All eligible subjects (n ¼ 95) received written information before enrollment and 90 agreed to enter the study. A spot clean-catch and midstream voided urine sample was collected from each patient for measurement of protein, creatinine and calcium immediately before routine 24-h urine collection.…”

“…1,2,[6][7][8]10,12,13 The latter measurement is also traditionally used for quantifying proteinuria in hypertensive pregnant women but has several limitations. [1][2][3][6][7][8][9][11][12][13][14][15][16][17][18] Most importantly, the laboratory results are not available to the clinician before 24 h, which may delay the ideal strategy for the immediate management of hypertension during pregnancy.…”

“…The accuracy of these investigations has been described in most studies of hypertensive and healthy pregnant women, 1,3,[5][6][7]11,[15][16][17][18][19][20][21] as well as nonpregnant healthy volunteers and patients with renal impairment. 15,17,18,22 These simple urine tests could assist in improving the clinical triage of hypertensive pregnant women with a potential for decreasing the workload of the maternity staff. It would also reduce the demand and cost of laboratory services particularly in resource-constrained settings, like our own, where HDP are particularly prevalent.…”

“…It would also reduce the demand and cost of laboratory services particularly in resource-constrained settings, like our own, where HDP are particularly prevalent. 5,6,8,17,18,[21][22][23] The aim of our study, therefore, was to evaluate the value of random urinary protein-creatinine and calcium-creatinine concentration in a consecutive sample of women with HDP in predicting 24-h proteinuria in our institution.…”