Spot urine protein‐to‐creatinine ratio as a diagnostic test in pre‐eclampsia: A gold standard?

Abstract

Objective To determine the diagnostic accuracy and optimal threshold of the spot protein‐to‐creatinine ratio (PCR) compared to the gold standard, 24‐hour proteinuria (24HP) in patients with suspected pre‐eclampsia. Methods A prospective observational study was performed from June 2015 to May 2017 consisting of patients hospitalized for suspected pre‐eclampsia in a tertiary care referral center. To compare the two diagnostic tests, a spot urine sample was obtained to perform the PCR before starting the collection of the 24HP. Only patients who had both tests were analyzed. Results In total, 148 patients (216 samples) were included. The two tests were highly correlated (r=0.80, P<0.001). The receiver operating characteristic curve analysis and the area under the curve (AUC=0.92) highlighted the accuracy of PCR in diagnosing significant proteinuria and thus pre‐eclampsia. The optimal cut‐off using the Liu method was 56.9 mg/mmol (sensitivity=79.3%, specificity=91.5%). Conclusion The results suggest that PCR could replace 24HP when diagnosing proteinuria in pre‐eclampsia. Moreover, it is a simple test, easy to realize and standardize, and cheap with no need for systematic hospitalization. The best cut‐off should be chosen by thinking about the risks for adverse maternal and/or fetal outcomes. The test may help to optimize medical care in pre‐eclampsia worldwide.

Relationship between proteinuria and optical coherence tomographic features of the chorioretina in patients with pre-eclampsia

“…Dong et al revealed that proteinuria in patients with pre-eclampsia is closely related to disease severity [ 27 ]. PCR is a simple, inexpensive and easily accessible method to assess the magnitude of proteinuria and the function of glomerular cell [ 16 , 28 , 29 ]. In this study, CT was significantly increased with elevated PCR.…”

Comparative evaluation of different methods to quantify proteinuria in preeclampsia

“…In study by Berthet et al, the area under the curve for spot PCR was 0.92, with higher accuracy in diagnosing the proteinuria and thus pre-eclampsia. 11 In a study, Sharma et al documented the AUC for PCR was 0.793, p<0.05. 7 On assessment of diagnostic accuracy in term of sensitivity, specificity, PPV, NPV and accuracy of each method compared with the 24-hour urinary total protein estimation.…”

Cross‐sectional diagnostic accuracy study of self‐testing for proteinuria during hypertensive pregnancies: The UDIP study

“…Previously, 24‐hour urine collection was considered the appropriate comparator for proteinuria quantification 8 but it has since been replaced in the UK with laboratory PCR testing. Recommended by NICE, 2 PCR testing is more accurate, 15 less time‐consuming and more convenient for women than 24‐hour urine collection 19,20 . The majority of studies examining point‐of‐care testing for proteinuria have used 24‐hour urine collection as a primary reference test, and those using PCR have not reported on self‐testing 21…”

“…Recommended by NICE, 2 PCR testing is more accurate, 15 less time-consuming and more convenient for women than 24-hour urine collection. 19,20 The majority of studies examining point-of-care testing for proteinuria have used 24-hour urine collection as a primary reference test, and those using PCR have not reported on self-testing. 21 A limitation to the study was that pregnant women performed a one-off test in a clinic environment.…”