The Accuracy of Urine Dipsticks as a Screening Test for Proteinuria in Hypertensive Disorders of Pregnancy

The diagnostic Accuracy of Visual versus automated dipstick proteinuria testing in Pregnancy: A systematic review and Meta-Analysis

OBJECTIVE

To evaluate the diagnostic accuracy of point-of-care (POC) tests for detecting proteinuria in pregnant women.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE and EMBASE databases were searched from inception to 13 November 2020.

ELIGIBILITY CRITERIA AND DATA ANALYSIS

Included studies measured the sensitivity and specificity ofPOC proteinuria testing compared to laboratory reference standards (protein-creatinine ratio (PCR), 24-hour urine collection). Bivariate meta-analyses determined pooled sensitivity and specificity. Random-effects inverse-variance model determinedheterogeneity.

MAIN OUTCOME MEASURES

The primary outcome was overall sensitivity and specificity, stratified by method of POC testing and reference standard. Secondary outcomes were sensitivity and specificity within thesubgroupstest brand, reference standard, and hypertension status.

RESULTS

1078 studies were identified, 17 studies comprising 23 comparisons were included. The meta-analysis included 13 studies with 19 comparisons. Pooled sensitivity and specificity of visual dipsticks against PCR was 72 % (95 % CI: 56 % to 84 %) and 92 % (95 % CI: 76 % to 98 %), respectively. Pooled sensitivity and specificity of visual dipsticks against 24-hour collection was 69 % (55 % to 80 %) and 70 % (51 % to 84 %), respectively. Pooled sensitivity and specificity for automated readers against PCR was 73 % (53 % to 86 %) and 91 % (83 % to 95 %), respectively. Pooled sensitivity and specificity of automated readers against 24-hour collection was 65 % (42 % to 83 %) and 82 % (46 % to 96 %), respectively.

CONCLUSION

Visual dipsticks have comparable accuracy to automated readers, yet are notadequate as a rule-out test for proteinuria. Proteinuria POC testing maybe beneficial inantenatal care when repeatfollow-up tests are performed. PROSPERO Registration Number: CRD42021231914.

Antenatal care policy in high-income countries with a universal health system: A scoping review

The availability, effectiveness, and access to antenatal care are directly linked with good maternal and neonatal outcomes, making antenatal care an important determinant in health. But to be effective, care must always be appropriate, not excessive, not insufficient. Perinatal outcomes vary within and between countries, raising questions about practices, the use of best evidence in clinical decisions and the existence of clear and updated guidance. Through a scoping review methodology, this study aimed to map the available antenatal care policies for low-risk pregnant women in high-income countries with a universal health system, financed by the government through tax payments. Following searches on the main databases and grey literature, the authors identified and analysed ten antenatal care policies using a previously piloted datachart: Australia, Denmark, Finland, Iceland, Italy, Norway, Portugal, Spain, Sweden and the United Kingdom. Some policies were over 10 years old, some recommendations did not present a rationale or context, others were outdated, or were simply different approaches in the absence of strong evidence. Whilst some recommendations were ubiquitous, others differed either in the recommendation provided, the timing, or the frequency. Similarly, we found wide variation in the methods/strategy used to support the recommendations provided. These results confirm that best evidence is not always assimilated into policies and clinical guidance. Further research crossing these differences with perinatal outcomes and evaluation of cost could be valuable to optimise guidance on antenatal care. Similarly, some aspects of care need further rigorous studies to obtain evidence of higher quality to inform recommendations.

Diagnostic accuracy of urine dipstick tests for proteinuria in pregnant women suspected of preeclampsia: A systematic review and meta-analysis

OBJECTIVES

Dipstick tests are frequently used as bedside proteinuria tests to evaluate women suspected of preeclampsia and may inform diagnosis in low resource settings lacking laboratory facilities. This systematic review and meta-analysis aimed to (1) estimate the diagnostic accuracy of urine dipsticks in diagnosing proteinuria, (2) compare performance of different dipstick types and (3) estimate their related costs.

METHODS

MEDLINE and EMBASE were searched up to August 1, 2020 for primary studies with cross-sectional diagnostic accuracy data on dipstick test(s) compared to a laboratory reference standard (24-hour protein ≥ 300 mg or protein-creatinine ratio ≥ 30 mg/mmol) in pregnant women ≥ 20 weeks of gestation suspected of preeclampsia. Risk of bias and applicability was assessed with QUADAS-2. Data were analysed using a bivariate model with hierarchical addition of covariates for subgroups.

RESULTS

Nineteen studies were included. Protein-only dipsticks at 1 + threshold had a pooled sensitivity of 0.68 [95%CI: 0.57-0.77] and specificity of 0.85 [95% CI: 0.73-0.93] (n = 3700 urine samples, 18 studies). Higher specificity was found with automatedly (0.93 [95% CI: 0.82-0.98]) compared to visually (0.81 [95% CI: 0.65-0.91]) read dipsticks, whereas sensitivity was similar and costs were higher. The use of albumin-creatinine ratio (ACR) dipsticks was only reported in two studies and did not improve accuracy. Heterogeneity in study design and prevalence of preeclampsia amongst studies complicated interpretation of pooled estimates.

CONCLUSION

Urine dipsticks performed poorly at excluding preeclampsia in hypertensive pregnant women. Further development of accurate and low-cost bedside proteinuria tests is warranted.

A simplified point-of-care testing approach for preeclampsia blood biomarkers based on nanoscale field effect transistors

Rapid diagnosis of preeclampsia is necessary to ensure timely administration of appropriate care and prevent the potentially catastrophic complications of the condition affecting both mothers and babies. While the diagnostic superiority of angiogenic blood biomarkers such as placental growth factor has recently been demonstrated, there is an urgent need to develop point-of-care (PoC) technologies that allow rapid, quantitative, and accurate testing for these markers within local communities. Towards addressing this need, here we report on a fully integrated biodiagnostic platform based on nanoscale indium oxide field effect transistor (FET) sensors. The high-performance FET sensors are integrated with blood sample processing cartridges that minimize the need for operator intervention during the assay and eliminate the need for analytical equipment. Within 40 minutes and from 30 μL of blood, the FET platform could reliably measure PlGF with a limit of detection of 0.06 pg mL^-1 and a five order of magnitudes dynamic range. Pilot clinical validation in four preeclamptic pregnancies confirmed that the accuracy and reliability of the FET platform, paving the way for further development to a much-needed point-of-care preeclampsia testing.

The function of adipsin and C9 protein in the complement system in HIV-associated preeclampsia

OBJECTIVE

In preeclampsia, there are excessive complement components expressed due to increased complement activation; therefore, this study investigated the concentration of adipsin and C9 in HIV-associated preeclampsia.

METHOD

The study population (n = 76) was stratified by pregnancy type (normotensive pregnant and preeclampsia) and by HIV status. Serum was assayed for the concentration of adipsin and C9 using a Bioplex immunoassay procedure.

RESULTS

Maternal weight did not differ (p = 0.1196) across the study groups. The concentration of adipsin was statistically different between the PE vs normotensive pregnant groups, irrespective of HIV status (p = 0.0439). There was no significant difference in adipsin concentration between HIV-negative vs HIV-positive groups, irrespective of pregnancy type (p = 0.6290). Additionally, there was a significant difference in adipsin concentration between HIV-negative normotensive vs HIV-negative preeclampsia (p < 0.05), as well as a difference between HIV-negative preeclampsia vs HIV-positive preeclampsia (p < 0.05). C9 protein expression was not statistically different between the normotensive and PE groups, regardless of HIV status (p = 0.5365). No statistical significance in C9 expression was found between HIV-positive vs HIV-negative groups, regardless of pregnancy type (p = 0.3166). Similarly, no statistical significance was noted across all study groups (p = 0.0774).

CONCLUSION

This study demonstrates that there is a strong correlation between the up-regulation of adipsin and PE and that adipsin is a promising biomarker to use as a diagnostic tool for PE.

Evaluation of Acridine Orange Staining for a Semi-Automated Urinalysis Microscopic Examination at the Point-of-Care

A urinary tract infection (UTI) can be diagnosed via urinalysis, consisting of a dipstick test and manual microscopic examination. Point-of-care (POC) image-based systems have been designed to automate the microscopic examination for low-volume laboratories or low-resource clinics. In this pilot study, acridine orange (AO) was evaluated as a fluorescence-based contrast agent to aid in detecting and enumerating urine sediment specific for diagnosing a UTI. Acridine orange staining of epithelial cells, leukocytes, and bacteria provided sufficient contrast to successfully implement image segmentation techniques, which enabled the extraction of classifiable morphologic features. Surface area bounded by each cell border was used to differentiate the sediment; epithelial cells were larger than 500μm², bacteria were less than 30μm², and leukocytes in between. This image-based semi-automated technique using AO resulted in similar cell counts to the clinical results, which demonstrates the feasibility of AO as an aid for POC urinalysis systems.

Effect of the drug combination of magnesium sulfate and phentolamine on homocysteine and C-reactive protein in the serum of patients with pregnancy-induced hypertension syndrome

Effect and clinical efficacy of magnesium sulfate combined with phentolamine on homocysteine and C-reactive protein in the serum of patients with pregnancy-induced hypertension syndrome were investigated. A total of 96 patients with pregnancy-induced hypertension syndrome who were diagnosed and treated in Jining No. 1 People's Hospital from February 2016 to January 2018 were retrospectively analyzed. The patients were grouped according to the dosage regimen. The patients who received the combination treatment of magnesium sulfate and phentolamine on the basis of magnesium sulfate were included in the observation group, and the patients who were treated with the intravenous infusion of magnesium sulfate alone were included in the control group. Mean arterial pressure (MAP), the content of 24 h urine protein, systolic blood pressure (SBP), diastolic blood pressure (DBP), Hcy, and CRP of the pregnant women were observed. MAP and the content of 24 h urine protein, SBP and DBP of the patients in the observation group after the treatment were significantly lower than those of the patients in the control group (P<0.001). Hcy and CRP of the patients in the observation group after the treatment were significantly lower than those of the patients in the control group (P<0.001). The total effective rate of the patients in the observation group was significantly higher than that of the patients in the control group (P<0.05). In conclusion, the meliorative effect of magnesium sulphate combined with phentolamine on the level of MAP, the content of 24 h urine protein, SBP, DBP, Hcy and CRP in pregnant woman had a greater impact than that of the single use of the intravenous infusion of magnesium sulfate in the treatment of pregnancy-induced hypertension syndrome, and the clinical efficacy of magnesium sulphate combined with phentolamine was better, thus worthwhile to promote widely in clinic.

The comparison of automated urine analyzers with manual microscopic examination for urinalysis automated urine analyzers and manual urinalysis

OBJECTIVES

Urinalysis is one of the most commonly performed tests in the clinical laboratory. However, manual microscopic sediment examination is labor-intensive, time-consuming, and lacks standardization in high-volume laboratories. In this study, the concordance of analyses between manual microscopic examination and two different automatic urine sediment analyzers has been evaluated.

DESIGN AND METHODS

209 urine samples were analyzed by the Iris iQ200 ELITE (İris Diagnostics, USA), Dirui FUS-200 (DIRUI Industrial Co., China) automatic urine sediment analyzers and by manual microscopic examination. The degree of concordance (Kappa coefficient) and the rates within the same grading were evaluated.

RESULTS

For erythrocytes, leukocytes, epithelial cells, bacteria, crystals and yeasts, the degree of concordance between the two instruments was better than the degree of concordance between the manual microscopic method and the individual devices. There was no concordance between all methods for casts.

CONCLUSION

The results from the automated analyzers for erythrocytes, leukocytes and epithelial cells were similar to the result of microscopic examination. However, in order to avoid any error or uncertainty, some images (particularly: dysmorphic cells, bacteria, yeasts, casts and crystals) have to be analyzed by manual microscopic examination by trained staff. Therefore, the software programs which are used in automatic urine sediment analysers need further development to recognize urinary shaped elements more accurately. Automated systems are important in terms of time saving and standardization.

Clinical assessment of the specificity of an adipsin rapid test for the diagnosis of preeclampsia

OBJECTIVE

To evaluate the specificity of the adipsin rapid test in clinical practice for the diagnosis of preeclampsia (PE).

METHODS

A total of 1144 pregnant women were recruited in this study: 44 pregnant women with PE and 1100 healthy pregnancies as controls. Urine samples were collected and used, respectively, for the adipsin rapid test and the urinary dipstick test for protein detection. Sensitivity and specificity were calculated on the basis of the detection results.

RESULTS

In the 1144 women examined with the adipsin rapid test for PE diagnosis, the sensitivity and specificity were 93.2% and 98.8%, respectively; the total accuracy was 98.6%. For the 1144 women tested with urinary dipstick, the sensitivity and specificity were 93.2% and 40.5%, respectively; and the total accuracy was 42.5%.

CONCLUSION

Both the adipsin rapid test and the urinary dipstick test are noninvasive and inexpensive rapid tests for the diagnosis of PE. However, the adipsin rapid test was proven more reliable since it had a higher sensitivity, specificity, and accuracy.

Urinary protein-to-creatinine ratio in pregnant women after dipstick testing: prospective observational study

Background

The dipstick test is widely used as a primary screening test for detection of significant proteinuria in pregnancy (SPIP). However, it often shows a false positive test result. This study was performed to determine which pregnant women should be recommended to undergo determination of urinary protein-to-creatinine ratio (mg/mg, P/Cr test) after dipstick test for confirmation of SPIP.

Methods

This was a multicenter, prospective, and observational study of 2212 urine specimens from 1033 pregnant women who underwent simultaneous dipstick and P/Cr tests in the same spot urine samples at least once. SPIP was defined as P/Cr > 0.27. Preeclampsia was diagnosed in women with both hypertension and SPIP.

Results

Preeclampsia, hypertension alone, and SPIP alone developed in 202 (20 %), 73 (7.1 %), and 120 (12 %) women, respectively. Creatinine concentration [Cr] varied greatly, ranging from 8.1 to 831 mg/dL in the 2212 urine samples. Rate of positive dipstick test results increased with increasing [Cr], while SPIP prevalence rate was lower in urine samples with higher [Cr], yielding higher false positive rates in samples with higher [Cr]. Postpartum urine samples had significantly lower [Cr] compared to those obtained antepartum (60 [8.7–297] vs. 100 [10–401] mg/dL, respectively). At the first P/Cr test among women with similar dipstick test results, the risk of having SPIP was consistently and significantly higher for hypertensive women than for normotensive women at any dipstick test result: 18 % (14/77) vs. 3.2 % (8/251), 47 % (26/55) vs. 8.7 % (37/425), 91 % (82/90) vs. 59 % (44/75) for negative/equivocal, 1+, and ≥ 2+ test results, respectively. The risk of SPIP was 16 % (9/55) for normotensive women when two successive antenatal urine samples showed a dipstick test result of 1 + .

Conclusions

For prediction of SPIP, the dipstick test was more likely to show a false positive result in concentrated urine samples with higher [Cr]. Hypertensive women with ≥ 1+ as well as normotensive women with ≥ 2+ on dipstick test should be advised to undergo the P/Cr test.

Diagnosis and Treatment of Hypertensive Pregnancy Disorders. Guideline of DGGG (S1-Level, AWMF Registry No. 015/018, December 2013)

Purpose: Official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG). Hypertensive pregnancy disorders contribute significantly to perinatal as well as maternal morbidity and mortality worldwide. Also in Germany these diseases are a major course for hospitalization during pregnancy, iatrogenic preterm birth and long-term cardiovascular morbidity. Methods: This S1-guideline is the work of an interdisciplinary group of experts from a range of different professions who were commissioned by DGGG to carry out a systematic literature search of positioning injuries. Members of the participating scientific societies develop a consensus in an informal procedure. Afterwards the directorate of the scientific society approves the consensus. Recommendations: This guideline summarizes the state-of-art for classification, risk stratification, diagnostic, treatment of hypertensive pregnancy disorders.

Strong correlation between protein reagent strip and protein-to-creatinine ratio for detection of renal dysfunction in HIV-infected patients: a cross-sectional study

Background

Tubular dysfunction is common in HIV-infected people and detection of proteinuria is essential to identify this problem. In low-income countries, resources for detection of proteinuria using the Kidney Disease Improve Global Outcomes (KDIGO) gold standard urinary protein/creatinine ratio (uPCR) is rarely possible, and use of the protein reagent strip (PRS) could be an option in these places. The aims of this study were to establish the concordance between PRS and uPCR to detect tubular proteinuria in HIV-infected people, and to assess the sensitivity and specificity of PRS as a diagnostic method in this group.

Methods

A cross-sectional study was conducted to evaluate the correlation between the two techniques to detect protein in urine. Participants were enrolled for a period of 6 months. The measurements were performed in participants who were on highly active antiretroviral therapy (HAART) or prior to the start of treatment. Proteinuria was defined as uPCR ≥ 150 mg/g, and/or ≥ trace on PRS. A phi coefficient was calculated to establish the degree of correlation. We assessed the sensitivity and specificity of PRS compared with uPCR using standard methods.

Results

A total of 799 subjects were included. Of these, 737 (92%) were men. The mean age was 32.9 years (±10.1 years). Most (561, 70%) were on antiretroviral treatment. The mean estimated glomerular filtration rate (eGFR) calculated according to Modification of Diet in Renal Disease (MDRD)-4 was 113.0 mL/min (±22.6). Comorbidities included diabetes mellitus (10, 1.3%) and hypertension (17, 2.1%). The prevalence of proteinuria detected by PRS was 8.3% (n = 66) and by uPCR 10.6% (n = 85). The concordance assessed by phi correlation coefficient was 0.70, p < 0.001, with a sensitivity of 51.7% (95% confidence interval [CI] 41%–62%) and specificity 97% (95% CI 39%–97%).

Conclusions

There is a high concordance between detection of proteinuria by PRS and uPCR. Therefore, in low-income countries PRS can be helpful for detecting tubular damage in people infected with HIV.

Elevation of urinary adipsin in preeclampsia: correlation with urine protein concentration and the potential use for a rapid diagnostic test

Early diagnosis and treatment of preeclampsia are essential for prevention of seizure development and fetus maturation. Although various methods have been developed for predicting or monitoring the onset of preeclampsia, a simple assay that can be used as a home or point of care test remains unavailable. We attempted to find a urinary protein that could be used as a biomarker for developing such a test. Urinary samples were collected from 124 preeclampsia and 135 healthy pregnant women for screening using a protein array technology and quantification by ELISA. A urinary protein, adipsin, was found significantly increased, and the adipsin creatinine ratio was closely correlated with the urinary 24-hour protein in patients with preeclampsia. When combined with the increased diastolic blood pressure (≥90 mm Hg), the sensitivity was 90.3% and the specificity reached 100.0% for preeclampsia diagnosis. We then developed a laminar flow immunoassay for rapid diagnosis, and the sensitivity and specificity were 89.04% and 100%, respectively, when combined with increased diastolic blood pressure. Because of the easiness of sample collection, assay conduction, and result interpretation, this urine test can be potentially used as a home test for monitoring preeclampsia onset for high-risk pregnant women and as a rapid test for a preliminary diagnosis for emergency patients at hospitals.

Clinical significance of proteinuria determined with dipstick test, edema, and weekly weight gain ⩾500g at antenatal visit

OBJECTIVE

To determine how urine dipstick test, edema, and/or excessive weight gain (EWG, defined as ⩾500g/week) at antenatal visits predict significant proteinuria (defined as a protein-to-creatinine ratio [P/Cr, mg/mg] ⩾0.27) and preeclampsia.

METHODS

Data from 3279 antenatal visits between 30 and 36weeks of gestation were studied in 783 women with singleton pregnancies. In 24 preeclamptic pregnancies, data from 89 antenatal visits at and before diagnosis of preeclampsia were used. Spot P/Cr was determined in women with repeated positive dipstick test results in two successive antenatal visits or in those with a positive dipstick test result tested in the presence of hypertension.

RESULTS

Proteinuria on dipstick test, edema, and EWG appeared often in both women with and without preeclampsia; 66.7% vs. 27.7%, 83.3% vs. 44.1%, and 91.7% vs. 81.6%, respectively. However, repeated positive dipstick test results in two successive antenatal visits yielded sensitivity of 45.5%, specificity of 95.2%, and positive and negative predictive values of 30.0% and 97.4%, respectively, for detection of significant proteinuria and corresponding figures of 33.3%, 94.1%, 14.0%, and 98.0% for prediction of preeclampsia.

CONCLUSION

Repeated positive dipstick test results in two successive antenatal visits warrant a need for a confirmation test of significant proteinuria.

Recent and potential developments in the analysis of urine: a review

Analysis of urine is a widely used diagnostic tool that traditionally measured one or, at most, a few metabolites. However, the recognition of the need for a holistic approach to metabolism led to the application of metabolomics to urine for disease diagnostics. This review looks at various aspects of urinalysis including sampling and traditional approaches before reviewing recent developments using metabolomics. Spectrometric approaches are covered briefly since there are already a number of very good reviews on NMR spectroscopy and mass spectrometry and other spectrometries are not as highly developed in their applications to metabolomics. On the other hand, there has been a recent surge in chromatographic applications dedicated to characterising the human urinary metabolome. While developments in the analysis of urine encompassing both classical approaches of urinalysis and metabolomics are covered, it must be emphasized that these approaches are not orthogonal - they both have their uses and are complementary. Regardless, the need to normalise analytical data remains an important impediment.

Vitamins C and E to prevent complications of pregnancy-associated hypertension

BACKGROUND

Oxidative stress has been proposed as a mechanism linking the poor placental perfusion characteristic of preeclampsia with the clinical manifestations of the disorder. We assessed the effects of antioxidant supplementation with vitamins C and E, initiated early in pregnancy, on the risk of serious adverse maternal, fetal, and neonatal outcomes related to pregnancy-associated hypertension.

METHODS

We conducted a multicenter, randomized, double-blind trial involving nulliparous women who were at low risk for preeclampsia. Women were randomly assigned to begin daily supplementation with 1000 mg of vitamin C and 400 IU of vitamin E or matching placebo between the 9th and 16th weeks of pregnancy. The primary outcome was severe pregnancy-associated hypertension alone or severe or mild hypertension with elevated liver-enzyme levels, thrombocytopenia, elevated serum creatinine levels, eclamptic seizure, medically indicated preterm birth, fetal-growth restriction, or perinatal death.

RESULTS

A total of 10,154 women underwent randomization. The two groups were similar with respect to baseline characteristics and adherence to the study drug. Outcome data were available for 9969 women. There was no significant difference between the vitamin and placebo groups in the rates of the primary outcome (6.1% and 5.7%, respectively; relative risk in the vitamin group, 1.07; 95% confidence interval [CI], 0.91 to 1.25) or in the rates of preeclampsia (7.2% and 6.7%, respectively; relative risk, 1.07; 95% CI, 0.93 to 1.24). Rates of adverse perinatal outcomes did not differ significantly between the groups.

CONCLUSIONS

Vitamin C and E supplementation initiated in the 9th to 16th week of pregnancy in an unselected cohort of low-risk, nulliparous women did not reduce the rate of adverse maternal or perinatal outcomes related to pregnancy-associated hypertension (ClinicalTrials.gov number, NCT00135707).

The diagnosis and treatment of hypertensive disorders of pregnancy: new findings for antenatal and inpatient care

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are among the leading causes of maternal and fetal morbidity and mortality. New guidelines and findings from clinical trials must be taken into account so that the diagnosis and treatment of HDP can be optimized.

METHODS

Current guidelines, Cochrane reviews, metaanalyses, and randomized, controlled trials were retrieved by a search in PubMed and the Cochrane Library for reports published from 2006 to March 2009. These publications were then analyzed and evaluated for their evidence levels (EL).

RESULTS AND CONCLUSIONS

Aside from hypertension and proteinuria, the definition of preeclampsia (PE) should also take organ dysfunction into account. Important aspects of antenatal care include the following: the early recognition of risk factors, measurement of the uterine arteries in the 1st and 2nd trimesters with Doppler ultrasonography (A diagnostic tool which is now well established), prophylactic oral administration of 100 mg of acetylsalicylic acid daily from the beginning of pregnancy, particularly in high-risk patients (EL I++), and appropriate measurement of blood pressure and urinary protein. Patients should be hospitalized whenever indicated. Therapeutic goals are adequate treatment of hypertension, as well as seizure prophylaxis with magnesium sulphate in severe preeclampsia to prevent maternal cerebrovascular complications (EL I++). If delivery is indicated, it should be performed, regardless of the gestational age (EL IV). Careful monitoring during the puerperium and a general medical review six weeks after delivery are essential. Women with preeclampsia have a significantly elevated long-term risk of developing cardiovascular diseases in later life (EL I++).

Comparison of pregnancy outcomes in women with hypertensive disorders of pregnancy using 24-hour urinary protein and urinary microalbumin to creatinine ratio

OBJECTIVE

To determine the role of proteinuria estimated using the 24-hour urinary protein test and the spot urinary microalbumin to creatinine ratio on the outcomes of pregnancy in women with hypertensive disorders of pregnancy.

METHODS

A total of 163 hypertensive women were recruited. Maternal and perinatal outcomes in women with and without significant proteinuria were compared using the diagnostic accuracy of the two tests.

RESULTS

Women with significant proteinuria determined using the 24-hour urinary protein test delivered at an earlier gestational age, had higher rates of induced labor, and lower birth weights compared with women who had gestational hypertension. No significant differences in outcomes were noted using the diagnostic accuracy of the spot urinary microalbumin to creatinine ratio dipstick.

CONCLUSION

The spot urinary microalbumin to creatinine ratio dipstick is a good screening test to rule out clinically significant proteinuria.

Use of 24-hour urinary protein and calcium for prediction of preeclampsia

OBJECTIVE

To assess the efficacy of 24-hour urinary protein and calcium for the prediction of preeclampsia.

MATERIALS AND METHODS

Two hundred normotensive women at 20-28 weeks' gestation were enrolled in the study. All women were asked to collect a 24-hour urine sample. Urinary protein and calcium were measured and expressed as milligrams per 24 hours. Sensitivity, specificity and predictive values were calculated for each test, and cutoff values were calculated using receiver operating characteristic curves.

RESULTS

Twenty-one of the 200 women developed preeclampsia, including eight who developed severe preeclampsia and 13 who developed mild preeclampsia. Compared with the normotensive women (n = 179), the hypertensive patients (n = 21) had significantly lower urinary calcium excretion (167.23 +/- 80.63 mg vs. 277.43 +/- 60.38 mg) and higher proteinuria (351.14 +/- 41.58 mg vs. 296.33 +/- 30.03 mg).

CONCLUSION

A decrease in 24-hour urinary calcium and increase in protein between 20-28 weeks' gestation are risk factors for preeclampsia.

Accuracy of the spot urinary microalbumin:creatinine ratio and visual dipsticks in hypertensive pregnant women

OBJECTIVES

New developments in proteinuria assessment have included the use of spot urinary microalbumin to creatinine ratio measurements. This study determines the accuracy of spot urinary microalbumin to creatinine ratio dipsticks and conventional visual dipsticks compared to the 24h urinary protein (gold standard) to detect significant proteinuria in hypertensive pregnant women.

STUDY DESIGN

163 women presenting with pregnancy hypertension were recruited from antenatal clinics. On admission each participant had a spot urine sample tested using a semi-quantitative visual dipstick and a spot midstream urine sample collected and analysed using the semi-quantitative urinary microalbumin to creatinine ratio dipsticks read instrumentally on the Clinitek 50 urine chemistry analyser. A 24 h urinary protein estimation was then performed. The results of the urinary microalbumin to creatinine ratio dipsticks and the conventional visual dipsticks were compared to the 24 h urine protein. A urinary microalbumin to creatinine ratio of > or =300 mg/g (1+ to 4+ on urine dipsticks) was considered a positive result > or =0.3g/24 h was considered significant proteinuria.

RESULTS

The visual dipstick had a sensitivity of 51% (95% CI [0.41-0.61]) and specificity of 91% (95% CI [0.81-0.96]). The PPV and NPV was 89% (95% CI [0.77-0.95]) and 58% (95% CI [0.48-0.67]), respectively. The urinary microalbumin to creatinine ratio dipsticks had a sensitivity of 63% (95% CI [0.52-0.72]) and specificity of 81% (95% CI [0.70-0.89]). The PPV was 82% (95% CI [0.71-0.90]) and NPV was 62% (95% CI [0.51-0.71]).

CONCLUSION

Neither the visual dipstick nor the urinary microalbumin to creatinine ratio dipstick read on the Clinitek 50 system is accurate when compared to the total 24h urinary protein. Differences between the urinary microalbumin to creatinine ratio and 24h total urinary protein may be due to the variation in the albumin fraction of the total urinary protein of pre-eclampsia, technical problems with imprecision of the assay technique, and clinical causes of false positives and negatives. The improved sensitivity of the automated urinary microalbumin to creatinine ratio dipstick over the visual dipstick suggests it may be a suitable substitute for the visual dipstick in clinical practice.

Automated urinalysis: first experiences and a comparison between the Iris iQ200 urine microscopy system, the Sysmex UF-100 flow cytometer and manual microscopic particle counting

BACKGROUND

Automated analysis of insoluble urine components can reduce the workload of conventional microscopic examination of urine sediment and is possibly helpful for standardization. We compared the diagnostic performance of two automated urine sediment analyzers and combined dipstick/automated urine analysis with that of the traditional dipstick/microscopy algorithm.

METHODS

A total of 332 specimens were collected and analyzed for insoluble urine components by microscopy and automated analyzers, namely the Iris iQ200 (Iris Diagnostics) and the UF-100 flow cytometer (Sysmex).

RESULTS

The coefficients of variation for day-to-day quality control of the iQ200 and UF-100 analyzers were 6.5% and 5.5%, respectively, for red blood cells. We reached accuracy ranging from 68% (bacteria) to 97% (yeast) for the iQ200 and from 42% (bacteria) to 93% (yeast) for the UF-100. The combination of dipstick and automated urine sediment analysis increased the sensitivity of screening to approximately 98%.

CONCLUSIONS

We conclude that automated urine sediment analysis is sufficiently precise and improves the workflow in a routine laboratory. In addition, it allows sediment analysis of all urine samples and thereby helps to detect pathological samples that would have been missed in the conventional two-step procedure according to the European guidelines. Although it is not a substitute for microscopic sediment examination, it can, when combined with dipstick testing, reduce the number of specimens submitted to microscopy. Visual microscopy is still required for some samples, namely, dysmorphic erythrocytes, yeasts, Trichomonas, oval fat bodies, differentiation of casts and certain crystals.