Microalbumin measurement alone or calculation of the albumin/creatinine ratio for the screening of hypertension patients?

Abstract Background. Spot urine sampling seems to be a reliable screening method for the detection of microalbuminuria in hypertensive patients. It remains unclear whether microalbumin measurement alone or calculation of the albumin/creatinine ratio (ACR) are more reliable for the detection of microalbuminuria in non-selected hypertensive patients. Methods. Following collection of a spot, midstream urine sample, urine was collected for 24 h for the measurement of microalbumin in 264 hypertensive patients. We compared microalbumin concentration in the spot urine with microalbumin measured in the 24-h urine sample and examined the utility of the ACR in evaluating microalbuminuria in hypertensive patients. Pathologic microalbuminuria was assumed when the microalbumin concentration exceeded 30 mg/l in the 24-h urine sample. Diagnostic performance is expressed in terms of specificity, sensitivity, positive (PPV) and negative predictive value (NPV), and area under receiver operating characteristics curve (AUC). Results. A total of 47 samples (17.8%) showed pathologic microalbuminuria in the 24-h urine sample. The diagnostic performance expressed as AUC was 0.94 (95% CI 0.90–0.98) for microalbumin measurement alone and 0.94 (95% CI 0.89–0.97) for ACR. The PPV and NPV were 44.2 and 97.9% for microalbumin measurement alone. ACR revealed a PPV of 29.3% and a NPV of 96.2% for males and 42.9 and 98% for females, if a cut-off value of 2.5 mg/mmol for males and of 4.0 mg/mmol for females was used. Conclusions. The ACR did not provide any advantage compared with microalbumin measurement alone, but requires an additional determination of creatinine and the use of gender-specific cut-off values. Therefore, measurement of microalbuminuria alone in the spot urine sample is more convenient in daily clinical practice and should be used as the screening method for hypertensive patients.

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POTASSIUM TO CREATININE RATIO IN A SPOT URINE SAMPLE IS A RELIABLE MEASURE OF 24-HOUR URINARY POTASSIUM EXCRETION IN HYPERTENSIVE PATIENTS

Journal of Hypertension ◽

10.1097/00004872-200406002-00337 ◽

2004 ◽

Vol 22 (Suppl. 2) ◽

pp. S97-S98 ◽

Cited By ~ 1

Author(s):

P. Jedrusik ◽

B. Symonides ◽

J. Chodakowska ◽

M. Dutkiewicz-Raczkowska ◽

Z. Gaciong

Keyword(s):

Urine Sample ◽

Potassium Excretion ◽

Creatinine Ratio ◽

Reliable Measure ◽

Hypertensive Patients ◽

Spot Urine ◽

Spot Urine Sample ◽

Urinary Potassium

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Comparison of single spot urinary albumin-creatinine ratio with 24-hour urinary protein excretion in women with preeclampsia

International Journal of Reproduction Contraception Obstetrics and Gynecology ◽

10.18203/2320-1770.ijrcog20181931 ◽

2018 ◽

Vol 7 (5) ◽

pp. 1929

Author(s):

Indu Kaul ◽

Bawa Ram Bhagat ◽

Deepika Sharma ◽

Gagan Singh

Keyword(s):

Urine Sample ◽

Predictive Value ◽

Solute Concentration ◽

Urinary Protein Excretion ◽

Urinary Protein ◽

Creatinine Ratio ◽

Albumin Creatinine Ratio ◽

Single Spot ◽

Spot Urine ◽

Protein Excretion

Background: The measurement of albumin: creatinine ratio (ACR) in a spot urine sample avoids the influence of variation in urinary solute concentration and provides a more convenient and rapid method to assess protein excretion. The aim of this study was to evaluate urinary spot ACR as a new marker for proteinuria and to study its correlation and accuracy in comparison with 24-hour urinary protein.Methods: The prospective one-year study was conducted on 100 pregnant women, 18-40 years, >20 weeks gestation with a diagnosis of preeclampsia. A spot midstream urine sample was taken for detection of albuminuria by dipstick method. Another spot sample was taken for detection and calculation of spot ACR. The 24-hour urine collection was taken immediately afterward to evaluate 24-hour urinary protein excretion.Results: A positive linear relation exists between ACR and 24-hour urinary protein excretion The ROC revealed cut-off of 20.4 with 88.5% sensitivity, 75% specificity, 98.8% positive predictive value and 21.4% negative predictive value. Spot urinary ACR >20.4 correctly identified women having 24-hour urinary protein excretion in excess of 0.3 gm/DL.Conclusions: A strong correlation exists between single spot urinary ACR with 24-hour urinary protein excretion in women with preeclampsia.

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Determining an Upper Reference Value for the Urinary Fluoride-Creatinine Ratio in Healthy Children Younger than 7 Years

Caries Research ◽

10.1159/000472263 ◽

2017 ◽

Vol 51 (4) ◽

pp. 283-289 ◽

Cited By ~ 3

Author(s):

F. Vida Zohoori ◽

A. Maguire

Keyword(s):

Urine Sample ◽

Strong Association ◽

Reference Value ◽

Epidemiological Studies ◽

Healthy Children ◽

Strong Positive Correlation ◽

Creatinine Ratio ◽

Spot Urine ◽

Spot Urine Sample ◽

Urinary Fluoride

The urinary fluoride/creatinine ratio (UF/Cr) in a spot urine sample could be a useful systemic F exposure monitoring tool. No reference value for UF/Cr currently exists, therefore this study aimed to establish an upper reference value for a UF/Cr, corresponding to excessive systemic F exposure, i.e., >0.07 mg F/kg body weight (b.w.)/day, in children. Subsidiary aims were to examine the relationship between (i) total daily F intake (TDFI) and 24-h urinary F excretion (DUFE); (ii) DUFE and UF/Cr, and (iii) TDFI and UF/Cr. Simultaneously collected TDFI, DUFE, and urinary creatinine (UCr) data in children <7 years were taken from UK studies conducted from 2002 to 2014 in order to calculate UF/Cr (mg/g) for each child. For the 158 children (mean age 5.8 years) included in the data analysis, mean TDFI and DUFE were 0.049 (SD 0.033) and 0.016 (SD 0.008) mg/kg b.w./day, respectively, and the mean UF/Cr was 1.21 (SD 0.61) mg/g. Significant (p < 0.001) positive linear correlations were found between TDFI and DUFE, DUFE and UF/Cr, and TDFI and UF/Cr. The estimated upper reference value for UF/Cr was 1.69 mg/g; this was significantly (p = 0.019) higher than the UF/Cr (1.29) associated with optimal F exposure (0.05-0.07 mg/kg b.w./day). In conclusion, the strong positive correlation between TDFI and UF/Cr confirms the strong association of these 2 F exposure variables and the value of a spot urine sample for prediction of TDFI (i.e., the most important risk factor in determining fluorosis occurrence and severity) in young children. Establishing an estimation of an upper reference value of 1.69 mg/g for UF/Cr in spot urine samples could simplify and facilitate their use as a valuable tool in large epidemiological studies.

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Spot protein–creatinine ratio and spot albumin–creatinine ratio in the assessment of pre-eclampsia: a diagnostic accuracy study with decision-analytic model-based economic evaluation and acceptability analysis

Health Technology Assessment ◽

10.3310/hta21610 ◽

2017 ◽

Vol 21 (61) ◽

pp. 1-90 ◽

Cited By ~ 12

Author(s):

Jason Waugh ◽

Richard Hooper ◽

Edmund Lamb ◽

Stephen Robson ◽

Andrew Shennan ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Urine Sample ◽

Cost Effective ◽

Creatinine Ratio ◽

Central Laboratory ◽

Albumin Creatinine Ratio ◽

Nice Guidelines ◽

Spot Urine ◽

Definition Of ◽

Rule Out

Background The National Institute for Health and Care Excellence (NICE) guidelines highlighted the need for ‘large, high-quality prospective studies comparing the various methods of measuring proteinuria in women with new-onset hypertensive disorders during pregnancy’. Objectives The primary objective was to evaluate quantitative assessments of spot protein–creatinine ratio (SPCR) and spot albumin–creatinine ratio (SACR) in predicting severe pre-eclampsia (PE) compared with 24-hour urine protein measurement. The secondary objectives were to investigate interlaboratory assay variation, to evaluate SPCR and SACR thresholds in predicting adverse maternal and fetal outcomes and to assess the cost-effectiveness of these models. Design This was a prospective diagnostic accuracy cohort study, with decision-analytic modelling and a cost-effectiveness analysis. Setting The setting was 36 obstetric units in England, UK. Participants Pregnant women (aged ≥ 16 years), who were at > 20 weeks’ gestation with confirmed gestational hypertension and trace or more proteinuria on an automated dipstick urinalysis. Interventions Women provided a spot urine sample for protein analysis (the recruitment sample) and were asked to collect a 24-hour urine sample, which was stored for secondary analysis. A further spot sample of urine was taken immediately before delivery. Main outcome measures Outcome data were collected from hospital records. There were four index tests on a spot sample of urine: (1) SPCR test (conducted at the local laboratory); (2) SPCR test [conducted at the central laboratory using the benzethonium chloride (BZC) assay]; (3) SPCR test [conducted at the central laboratory using the pyrogallol red (PGR) assay]; and (4) SACR test (conducted at the central laboratory using an automated chemistry analyser). The comparator tests on 24-hour urine collection were a central test using the BZC assay and a central test using the PGR assay. The primary reference standard was the NICE definition of severe PE. Secondary reference standards were a clinician diagnosis of severe PE, which is defined as treatment with magnesium sulphate or with severe PE protocol; adverse perinatal outcome; one or more of perinatal or infant mortality, bronchopulmonary dysplasia, necrotising enterocolitis or grade III/IV intraventricular haemorrhage; and economic cost and outcomes. Health service data on service use and costs followed published economic models. Results In total, 959 women were available for primary analysis and 417 of them had severe PE. The diagnostic accuracy of the four assays on spot urine samples against the reference standards was similar. The three SPCR tests had sensitivities in excess of 90% at prespecified thresholds, with poor specificities and negative likelihood ratios of ≥ 0.1. The SACR test had a significantly higher sensitivity of 99% (confidence interval 98% to 100%) and lower specificity. Receiver operating characteristic (ROC) curves were similar (area under ROC curve between 0.87 and 0.89); the area under the central laboratory’s SACR curve was significantly higher (p = 0.004). The central laboratory’s SACR test was the most cost-effective option, generating an additional 0.03 quality-adjusted life-years at an additional cost of £45.07 compared with the local laboratory’s SPCR test. The probabilistic analysis showed it to have a 100% probability of being cost-effective at the standard willingness-to-pay threshold recommended by NICE. Limitations Implementation of NICE guidelines has led to an increased intervention rate in the study population that affected recruitment rates and led to revised sample size calculations. Conclusions Evidence from this clinical study does not support the recommendation of 24-hour urine sample collection in hypertensive pregnant women. The SACR test had better diagnostic performance when predicting severe pre-eclampsia. All four tests could potentially be used as rule-out tests for the NICE definition of severe PE. Future work Testing SACR at a threshold of 8 mg/mmol should be studied as a ‘rule-out’ test of proteinuria. Trial registration Current Controlled Trials ISRCTN82607486. Funding This project was funded by the National Institute Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 61. See the NIHR Journals Library website for further project information.

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