A prospective comparison of total protein/creatinine ratio versus 24-hour urine protein in women with suspected preeclampsia

doi:10.1067/S0002-9378(03)00849-4

American Journal of Obstetrics and Gynecology

Volume 189, Issue 3, September 2003, Pages 848-852

https://doi.org/10.1067/S0002-9378(03)00849-4 Get rights and content

Abstract

Objective

The purpose of this study was to determine the value of the protein/creatinine ratio in prediction of 24-hour urine total protein among women with suspected preeclampsia.

Study design

Women who were evaluated for suspected preeclampsia at ≥24 weeks of gestation were studied prospectively if there was no concurrent diagnosis of chronic hypertension, diabetes mellitus, or preexisting renal disease. A protein/creatinine ratio was obtained, which was followed by the initiation of a 24-hour urine evaluation. Positive and negative predictive values and sensitivity and specificity of the protein/creatinine ratio for significant (≥300 mg) and severe proteinuria (≥5000 mg) that were based on 24-hour urine total protein were calculated.

Results

A total of 220 women were evaluated; 43.2% of the women were black, and 80% of the women had government insurance. Mean maternal and gestational ages were 26.1 years and 36.5 weeks, respectively. Significant and severe proteinuria on 24-hour urine evaluation were identified in 76.4% and 8.2% of cases, respectively. Regression analysis of protein/creatinine ratio and 24-hour urine total protein level showed a poor correlation (r² = 0.41). Receiver operator characteristic analysis revealed an area under the curve of 0.80, but the shoulder value of 390 mg/g carried a high false-negative rate (45.2%). With a more conservative cutoff value, a protein/creatinine ratio of ≥300 mg/g had a poor negative predictive value (47.5%), a specificity for significant proteinuria (55.8%), with a positive predictive value of 85.5%, and a sensitivity of 81%. For severe proteinuria, a protein/creatinine ratio of ≥5000 mg/g had a poor positive predictive value (61.9%) and sensitivity (72.2%), with a negative predictive value of 97.5%, and a specificity of 96.0%.

Conclusion

Protein/creatinine ratio does not exclude adequately the presence of significant proteinuria or predict severe proteinuria and should not be used as an alternative to 24-hour total protein evaluation.

Section snippets

Material and methods

The study was performed at MetroHealth Medical Center, a tertiary care referral center and affiliate of Case Western Reserve University, between January 2001 and July 2002, with institutional review board approval. Women with pregnancies of ≥24 weeks of gestation who were undergoing evaluation for “suspected preeclampsia” were studied prospectively. We included women who were undergoing evaluation for the possibility of preeclampsia on the basis of clinical findings that include ≥1 of following

Results

A total of 220 women completed both a random urinary protein/creatinine ratio and 24-hour urine collection during the study period; 43.2% of the women were black, and 80% of the women had government insurance. The mean maternal and gestational ages at collection were 26.1 years and 36.5 weeks, respectively. An indwelling Foley catheter was used in 89.1% of cases, and 94% of the 24-hour urine collections were obtained from inpatients on bed rest. The 6% of women whose progress was followed up as

Comment

Although previous studies have shown a strong correlation between protein/creatinine ratio and 24-hour urine total protein level in women who undergo evaluation for preeclampsia,9., 10. our results have shown a poor correlation between these two tests (r² = 0.41). With the cutoff point that was used clinically at our institution, we found that a protein/creatinine ratio of ≥300 mg/g accurately diagnoses significant proteinuria on 24-hour urine collection in most women. However, a

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2024, Biosensors and Bioelectronics
Pre-eclampsia is a serious multi-organ complication that severely threatens the safety of pregnant women and infants. To accurate and timely diagnose pre-eclampsia, point-of-care (POC) biosensing of the specific biomarkers is urgently required. However, one of the key biomarkers of pre-eclampsia, placental growth factor (PlGF), has a reduced level of expression in patients, which challenges the quantification capability and Limit-of-detection (LOD) of biosensors. Herein, we reported a microfiber Bragg grating biosensor for the quantification of PlGF in clinical serum samples. The Bragg grating was inscribed in a unilateral tapered fiber to generate the segmented Fabry-Perot spectrum for improving the capability of detection. Furthermore, a temperature-calibrated Bragg grating was added to enable dual parametric detection of PlGF and temperature simultaneously for removing the crosstalk. Finally, the biosensor was envisaged to be perfectly compatible with microfluidic chips, and thus dramatically reducing the sample consumption to as small as 10 μL. The proposed biosensor can respond to PlGF with concentrations ranging from 5 to 120 pg mL⁻¹, attaining a LOD of 5 pg mL⁻¹ of clinical relevance. More importantly, the biosensor achieved micro volume detection of clinical serum samples from patients, and the ROC curve with an AUC of 0.977 confirmed the viability of the device. Our study paves the way to a new idea for cost-effective and high-precision screening of patients with pre-eclampsia, and hence envisages a promising prospect for point-of-care (POC) diagnosis of patients with pre-eclampsia.
A meta-analysis on diagnostic accuracy of spot urinary protein to creatinine ratio versus 12-h proteinuria in preeclampsia
2024, iScience
To systematically review the diagnostic accuracy of spot urinary protein to creatinine ratio (PCR) and 12-h proteinuria in preeclampsia and to estimate which is a preferred alternative method for 24-h proteinuria, we carried out this meta-analysis. 25 primary studies were included based on searching strategy. For spot urinary PCR, our results showed pooled sensitivity of 87% (95% confidence interval [CI] 83%–91%) and specificity of 86% (95% CI 79%–91%), with an area under curve (AUC) of 0.93 (0.90–0.95). For 12-h proteinuria, pooled sensitivity and specificity were 92% (95% CI 87%–96%) and 99% (95% CI 75%–100%), respectively, with an AUC of 0.97 (0.95–0.98). Fagan plot and likelihood ratio scattergram showed that 12-h proteinuria yielded a better discriminatory performance on diagnosis of proteinuria (≥0.3 g/24 h). These results indicated that 12-h proteinuria estimation shows better clinical value than spot urine PCR for diagnosis of preeclampsia. However, due to the severity of condition and the fact that preeclampsia patients cannot wait for 12 h, spot urine PCR can be used as one of the diagnostic indicators.
Comparison of random urine protein/creatinine ratio with 24-hour urine protein in suspected pre-eclampsia
2023, Practical Laboratory Medicine
Proteinuria is one of the classical criteria for the diagnosis of pre-eclampsia. The gold standard remains the measurement of 24-h urine protein which is time consuming and prone to preanalytical errors. Random urine protein creatinine ratio (UPCR) is endorsed by clinical practice guidelines as a faster alternative. The aim of this study was to evaluate the correlation between the 24-h urine protein excretion and UPCR in the identification of proteinuria in suspected preeclamptic patients.
A total of 51 women with suspected pre-eclampsia from the maternal fetal clinic of our institution were retrospectively studied. The correlation between the UPCR in random urine samples and protein excretion in the 24-h urine collection was determined by Deming Regression analysis and Pearson correlation on EP evaluator and SPSS respectively.
There was a significant positive correlation between the numerical values obtained by 24-h urine protein and the UPCR (R = 0.88, P < 0.001). Concordance analysis showed 81.1% positive agreement for proteinuria between methods (>300 mg/24hr and >0.3) and 71.4% negative agreement. The clinical sensitivity and specificity of the UPCR was 74% and 69% respectively.
Overall, UPCR was well correlated with 24-h urine protein and could be an effective and compliant screening tool to indicate proteinuria in preeclamptic patients.
Protein-creatinine ratio and albumin-creatinine ratio for the diagnosis of significant proteinuria in pregnant women with hypertension: Systematic review and meta-analysis of diagnostic test accuracy
2021, Pregnancy Hypertension
Citation Excerpt :
The study flow chart is shown in Fig. 1. Twenty-eight studies reported on the diagnostic accuracy of PCR [9–36] and four reported on the diagnostic accuracy of ACR [16,28,30,37]. Four studies were retrospective cohort studies [9,21,23,25] 23 were prospective cohort studies [10–13,15–19,22,24,26–37] one descriptive cohort study [20] and one case-series [14].
The gold standard for assessment and diagnosis of significant proteinuria in pregnancy has been by 24-hour urine collection and analysis. Determining fast, accurate methods to identify clinically significant proteinuria would aid diagnosis of pre-eclampsia. The objective of this study was to determine the accuracy of spot protein-creatinine ratio (PCR) and albumin-creatinine ratio (ACR) measurements compared with 24-hour urine collection for the identification of clinically significant proteinuria in women with hypertensive disorders of pregnancy.
Search strategies were developed for electronic databases from inception to 1st October 2020. Data were assessed for methodological quality using the QUADAS-II checklist for risk of bias and quality of the evidence using GRADE. Meta-analysis was performed where there were at least four studies presenting data for the same comparison (test and threshold). This is an update of the review for NICE guideline NG133 (published June 2019) and includes additional data.
Twenty-nine studies were included. PCR measurements (28 studies) showed high sensitivity (91%) and specificity (89%) at a threshold of 30 mg/mmol (n = 3577). Higher thresholds (>60 mg/mmol) increased specificity, but reduced sensitivity. At a threshold of PCR 30 mg/mmol, diagnostic accuracy improved for sensitivity and specificity (93% for both) in studies where the first morning void was excluded (n = 1868).
Data available (4 studies) for ACR supports ruling out of significant proteinuria at less than 2 mg/mmol, though evidence was limited by paucity of data and wide confidence intervals around the result.
PCR and ACR have high accuracy compared to the gold standard 24-hour urine collection.
Differences in the prognosis of preeclampsia according to the initial symptoms: A single-center retrospective report
2019, Pregnancy Hypertension
Citation Excerpt :
As a simpler method, the pathological proteinuria assay based on the perinatal P/C ratio is useful in the diagnosis [14]. However, there are also negative perspectives [15–17] about it, and caution is therefore required in the interpretation of results. Even at this center, evaluation of proteinuria based on the P/C ratio was recently introduced.
Placental growth factor testing to assess women with suspected pre-eclampsia: a multicentre, pragmatic, stepped-wedge cluster-randomised controlled trial
2019, The Lancet
Previous prospective cohort studies have shown that angiogenic factors have a high diagnostic accuracy in women with suspected pre-eclampsia, but we remain uncertain of the effectiveness of these tests in a real-world setting. We therefore aimed to determine whether knowledge of the circulating concentration of placental growth factor (PlGF), an angiogenic factor, integrated with a clinical management algorithm, decreased the time for clinicians to make a diagnosis in women with suspected pre-eclampsia, and whether this approach reduced subsequent maternal or perinatal adverse outcomes.
We did a multicentre, pragmatic, stepped-wedge cluster-randomised controlled trial in 11 maternity units in the UK, which were each responsible for 3000–9000 deliveries per year. Women aged 18 years and older who presented with suspected pre-eclampsia between 20 weeks and 0 days of gestation and 36 weeks and 6 days of gestation, with a live, singleton fetus were invited to participate by the clinical research team. Suspected pre-eclampsia was defined as new-onset or worsening of existing hypertension, dipstick proteinuria, epigastric or right upper-quadrant pain, headache with visual disturbances, fetal growth restriction, or abnormal maternal blood tests that were suggestive of disease (such as thrombocytopenia or hepatic or renal dysfunction). Women were approached individually, they consented for study inclusion, and they were asked to give blood samples. We randomly allocated the maternity units, representing the clusters, to blocks. Blocks represented an intervention initiation time, which occurred at equally spaced 6-week intervals throughout the trial. At the start of the trial, all units had usual care (in which PlGF measurements were also taken but were concealed from clinicians and women). At the initiation time of each successive block, a site began to use the intervention (in which the circulating PlGF measurement was revealed and a clinical management algorithm was used). Enrolment of women continued for the duration of the blocks either to concealed PlGF testing, or after implementation, to revealed PlGF testing. The primary outcome was the time from presentation with suspected pre-eclampsia to documented pre-eclampsia in women enrolled in the trial who received a diagnosis of pre-eclampsia by their treating clinicians. This trial is registered with ISRCTN, number 16842031.
Between June 13, 2016, and Oct 27, 2017, we enrolled and assessed 1035 women with suspected pre-eclampsia. 12 (1%) women were found to be ineligible. Of the 1023 eligible women, 576 (56%) women were assigned to the intervention (revealed testing) group, and 447 (44%) women were assigned to receive usual care with additional concealed testing (concealed testing group). Three (1%) women in the revealed testing group were lost to follow-up, so 573 (99%) women in this group were included in the analyses. One (<1%) woman in the concealed testing group withdrew consent to follow-up data collection, so 446 (>99%) women in this group were included in the analyses. The median time to pre-eclampsia diagnosis was 4·1 days with concealed testing versus 1·9 days with revealed testing (time ratio 0·36, 95% CI 0·15–0·87; p=0·027). Maternal severe adverse outcomes were reported in 24 (5%) of 447 women in the concealed testing group versus 22 (4%) of 573 women in the revealed testing group (adjusted odds ratio 0·32, 95% CI 0·11–0·96; p=0·043), but there was no evidence of a difference in perinatal adverse outcomes (15% vs 14%, 1·45, 0·73–2·90) or gestation at delivery (36·6 weeks vs 36·8 weeks; mean difference −0·52, 95% CI −0·63 to 0·73).
We found that the availability of PlGF test results substantially reduced the time to clinical confirmation of pre-eclampsia. Where PlGF was implemented, we found a lower incidence of maternal adverse outcomes, consistent with adoption of targeted, enhanced surveillance, as recommended in the clinical management algorithm for clinicians. Adoption of PlGF testing in women with suspected pre-eclampsia is supported by the results of this study.
National Institute for Health Research.

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Supported in part by National Center for Research Resources, grant No. M01-RR-000080.

Presented at the Twenty-Third Annual Meeting of the Society for Maternal-Fetal Medicine, San Francisco, Calif, February 3-8, 2003.

Reprints not available from the authors.

View full text

A prospective comparison of total protein/creatinine ratio versus 24-hour urine protein in women with suspected preeclampsia☆

Abstract

Objective

Study design

Results

Conclusion

Section snippets

Material and methods

Results

Comment

Am J Obstet Gynecol

Am J Obstet Gynecol

Obstet Gynecol

Am J Obstet Gynecol

Am J Obstet Gynecol