Spot Urine Protein Measurements

Akbari, Ayub; White, Christine A.; Shahbazi, Nasim; Booth, Ronald A.; Hiremath, Swapnil; Knoll, Greg

doi:10.1097/tp.0b013e31825b413e

Cited by 15 publications

(7 citation statements)

References 27 publications

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“…Both are statistical measures of the performance of a binary classification and as such, none of these measures gives the clinician information about quantitative accuracy of the test. To date, only one study evaluated bias, precision and accuracy of PCR measurements and 24-h proteinuria in kidney transplant recipients [ 12 ]. However, the authors did not provide information which urine sample was analyzed and weather spot urine and 24-h urine were collected on the same day.…”

Section: Discussionmentioning

confidence: 99%

“…24-h proteinuria was corrected for standard body surface area by multiplying the measured value by 1.73 and dividing it by the patients’ body surface area. Estimation of 24-h protein excretion rate (ePER, mg/day/1.73m 2 ) was obtained by multiplying PCR and estimated creatinine excretion rate [ 12 , 16 ]. Percent bias, precision, and accuracy were calculated for the following values of 24-h proteinuria: 150 to 299 (mild proteinuria), 300 to 999 (moderate proteinuria), and 1000 or more mg/day/1.73m 2 (high-grade proteinuria) [ 17 , 18 ].…”

Section: Methodsmentioning

confidence: 99%

“…Only one study to date evaluated absolute agreement (i.e., bias, precision and accuracy) of PCR measurements and 24-h proteinuria in kidney transplant recipients [ 12 ]. Unfortunately, random spot urine PCR that were used as a representation of the 24-h urine collection show poor agreement with 24-h proteinuria [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

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First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

et al. 2021

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Background Quantification of proteinuria in kidney transplant recipients is important for diagnostic and prognostic purposes. Apart from correlation tests, there have been few evaluations of spot urine protein measurements in kidney transplantation. Methods In this cross-sectional study involving 151 transplanted patients, we investigated measures of agreement (bias and accuracy) between the estimated protein excretion rate (ePER), determined from the protein-to-creatinine ratio in the first and second morning urine, and 24-h proteinuria and studied their performance at different levels of proteinuria. Measures of agreement were reanalyzed in relation to allograft histology in 76 patients with kidney biopsies performed for cause before enrolment in the study. Results For ePER in the first morning urine, percent bias ranged from 1 to 28% and accuracy (within 30% of 24-h collection) ranged from 56 to 73%. For the second morning urine, percent bias ranged from 2 to 11%, and accuracy ranged from 71 to 78%. The accuracy of ePER (within 30%) in first and second morning urine progressively increased from 56 and 71% for low-grade proteinuria (150–299 mg/day) to 60 and 74% for moderate proteinuria (300–999 mg/day), and to 73 and 78% for high-grade proteinuria (≥1000 mg/day). Measures of agreement were similar across histologic phenotypes of allograft injury. Conclusions The ability of ePER to accurately predict 24-h proteinuria in kidney transplant recipients is modest. However, accuracy improves with an increase in proteinuria. Given the similar accuracy of ePER measurements in first and second morning urine, second morning urine can be used to monitor protein excretion.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

et al. 2021

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“…Exact 95% confidence intervals (CI) around accuracy measurements were calculated. Precision was assessed as the interquartile range of the median bias[8, 9]. Wilcoxon Rank-Sum Test was utilized to make the following comparisons: ACR versus mAER compared to eAER versus mAER and PCR versus mPER compared to ePER versus mPER.…”

Section: Methodsmentioning

confidence: 99%

“…Unfortunately, the absolute agreement between the ACR and PCR and the 24-hour urine collection is poor in both CKD and kidney transplant recipients [8, 9]. One possible explanation for the poor agreement is that ACR and PCR assume a creatinine (Cr) excretion rate of 1000 mg/day, an assumption that is not correct in many instances [10].…”

Section: Introductionmentioning

confidence: 99%

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients

et al. 2016

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BackgroundAgreement between spot and 24-hour urine protein measurements is poor in kidney transplant recipients. We investigated whether using formulae to estimate creatinine excretion rate (eCER), rather than assuming a standard creatinine excretion rate, would improve the estimation of proteinuria from spot urine samples in kidney transplant recipients.MethodsWe measured 24 hour urine protein and albumin and spot albumin:creatinine (ACR) and spot protein:creatinine (PCR) in 181 Kidney transplant recipients.” We utilized 6 different published formulae (Fotheringham, CKD-EPI, Cockcroft-Gault, Walser, Goldwasser and Rule) to estimate eCER and from it calculated estimated albumin and protein excretion rate (eAER and ePER). Bias, precision and accuracy (within 15%, 30% and 50%) of ACR, PCR, eAER, ePER were compared to 24-hour urine protein and albumin.ResultsACR and PCR significantly underestimated 24-hour albumin and protein excretion (ACR Bias (IQR), -5.9 mg/day; p< 0.01; PCR Bias, (IQR), -35.2 mg/day; p<0.01). None of the formulae used to calculate eAER or ePER had a bias that was significantly different from the 24-hour collection (eAER and ePER bias: Fotheringham -0.3 and 7.2, CKD-EPI 0.3 and 13.5, Cockcroft-Gault -3.2 and -13.9, Walser -1.7 and 3.1, Goldwasser -1.3 and -0.5, Rule -0.6 and 4.2 mg/day respectively. The accuracy for ACR and PCR were lower (within 30% being 38% and 43% respectively) than the corresponding values estimated by utilizing eCER (for eAER 46% to 49% and ePER 46–54%).ConclusionUtilizing estimated creatinine excretion to calculate eAER and ePER improves the estimation of 24-hour albuminuria/proteinuria with spot urine samples in kidney transplant recipients.

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Post-transplant Proteinuria: Differential Diagnosis and Management

Akbari

Knoll

2014

Kidney Transplantation

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Spot Urine Protein Measurements

Cited by 15 publications

References 27 publications

First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients

Post-transplant Proteinuria: Differential Diagnosis and Management

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