β-Trace Protein Assays: A Comparison Between Nephelometric and ELISA Methodologies

White, Christine A.; Akbari, Ayub; Eckfeldt, John H.; Chakraborty, Debarati; McCudden, Christopher R.; Flemming, Jennifer A.; Lowe, Catherine; Labrecque, Pascale; Parent, Jean Luc; Fergusson, Dean; Gill, John S.; Knoll, Greg

doi:10.1053/j.ajkd.2017.02.371

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…All in all our data did not show that BTP, in addition to creatinine and cystatin C, contains significant additional information on kidney function enabling a better distinction between disease-related and age-related “physiological” change of kidney function. Besides, the accuracy of BTP measurement is lower compared to creatinine and cystatin C 25 , 26 since a certified assay standardization has not yet been successfully established 27 , a fact that may also contribute to the rather disappointing results.…”

Section: Discussionmentioning

confidence: 99%

Beta Trace Protein does not outperform Creatinine and Cystatin C in estimating Glomerular Filtration Rate in Older Adults

Ebert

Koep

Schwarz

et al. 2017

Sci Rep

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Despite intense research the optimal endogenous biomarker for glomerular filtration rate (GFR) estimation has not been identified yet. We analyzed if ß-trace protein (BTP) improved GFR estimation in elderly. 566 participants aged 70+ from the population-based Berlin Initiative Study were included in a cross-sectional validation study. BTP, standardized creatinine and cystatin C were measured in participants with iohexol clearance measurement as gold standard method for measured GFR (mGFR). In a double logarithmic linear model prediction of mGFR by BTP was assessed. Analyses with BTP only and combined with creatinine and cystatin C were performed. Additionally, performance of GFR estimating equations was compared to mGFR. We found that the combination of all three biomarkers showed the best prediction of mGFR (r2 = 0.83), whereat the combination of creatinine and cystatin C provided only minimally diverging results (r2 = 0.82). Single usage of BTP showed worst prediction (r2 = 0.67) within models with only one biomarker. Subgroup analyses (arterial hypertension, diabetes, body mass index ≤23 and >30) demonstrated a slight additional benefit of including BTP into the prediction model for diabetic, hypertensive and lean patients. Among BTP-containing GFR equations the Inker BTP-based equation showed superior performance. Especially the use of cystatin C renders the addition of BTP unnecessary.

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Section: Discussionmentioning

confidence: 99%

Beta Trace Protein does not outperform Creatinine and Cystatin C in estimating Glomerular Filtration Rate in Older Adults

Ebert

Koep

Schwarz

et al. 2017

Sci Rep

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“…The immunonephelometric method performed using a BNII System (Siemens Healthcare) in this study was similar to that reported in other studies. However, there are still no higher order measurement, reference materials or standardised means of measuring BTP 31 to ensure reproducibility of results across laboratory. Therefore, even though the method of measurement used in this study was similar to that reported in earlier studies, we recognise that there will be differences in the specification of analytical measurements across different instruments that can influence the results.…”

Section: Discussionmentioning

confidence: 99%

Utility of serum beta-trace protein as a tool for estimating residual kidney function in peritoneal dialysis patients

et al. 2020

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Background: Beta-trace protein (BTP) is a novel marker for residual kidney function (RKF) without need for urinary collection. We aimed to examine its utility as a tool for estimating RKF in incident peritoneal dialysis (PD) patients. Methods: This was a post hoc analysis of incident PD patients from the balANZ trial cohort. The outcomes evaluated were trends of serum BTP concentration with time, factors associated with change in BTP using mixed-effect multilevel linear regression and correlation of BTP with mean urinary urea and creatinine clearances (measured glomerular filtration rate (GFR)). Performances of two BTP-derived equations (Shafi-Eqn and Steubl-Eqn) to estimate GFR were evaluated by reporting bias (median difference between estimated and measured GFR), precision (interquartile range of median bias), accuracy (±2 mL/min of measured GFR) and P30 (percentage estimates within 30% of measured GFR) with confidence intervals (CIs) generated by bootstrapping 2000 replicates. The agreement between BTP-estimated GFR and measured GFR was also plotted graphically on Bland–Altman analysis. Results: The study included 161 PD patients. BTP concentration increased with dialysis vintage and was inversely correlated with measured GFR ( r = −0.64). Larger increases in BTP were associated with longer PD vintage and higher dialysate glucose exposure. Biases of BTP-estimated GFRs (Shafi-Eqn and Steubl-Eqn) were 1.2 mL/min/1.73 m2 (95% CI 1.0–1.3 mL/min/1.73 m2) and 0.4 mL/min/1.73 m2 (95% CI 0.2–0.6 mL/min/1.73 m2), respectively. Both BTP-estimated GFRs had poor precision (3.2 mL/min/1.73 m2 (95% CI 2.9–3.5 mL/min/1.73 m2) and 2.8 mL/min/1.73 m2 (95% CI 2.5–3.2 mL/min/1.73 m2), respectively) and accuracy of estimates (55% (95% CI 52–60%) and 59% (95% CI 55–63%), respectively). The mean difference of BTP-estimated GFR (Shafi-Eqn and Steubl-Eqn) and measured GFR were −1.14 mL/min/1.73 m2 and −0.42 mL/min/1.73 m2, respectively, with large limit of agreement on Bland–Altman plot. Conclusions: Serum BTP level was inversely related to RKF but neither BTP-estimated GFR equations were sufficiently accurate for routine use in PD patients.

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“…17 A central aspect is the lack of standardization among available assays for both markers which results-as could be shown for BTP recently-in significant differences in BTP-based eGFRs. 18 The importance of assay standardization will be discussed further in the following.…”

Section: Determining Gfrmentioning

confidence: 99%

Determining the Glomerular Filtration Rate—An Overview

Schaeffner

2017

Journal of Renal Nutrition

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Correct determination of glomerular filtration rate (GFR) as an indicator of kidney function bears great importance because clinical decision-making depends on it at many occasions. During the last years, a huge body of literature has been published on estimation and measurement of GFR. The increasing pace with which novel estimation formulae, current and newer biomarkers, assay standardization procedures as well as invasive measurement methods of GFR were published, has been overwhelming for many clinicians. This concise review summarizes central issues in determining kidney function by listing some of the most important publications. It explains fundamental principles in GFR estimation and measurement, the influence of clinical characteristics on endogenous biomarkers, and obstacles in biomarker assessment. Thus, it is thought to be a guide for clinicians through the confusing jungle of GFR determination.

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β-Trace Protein Assays: A Comparison Between Nephelometric and ELISA Methodologies

Cited by 7 publications

References 6 publications

Beta Trace Protein does not outperform Creatinine and Cystatin C in estimating Glomerular Filtration Rate in Older Adults

Beta Trace Protein does not outperform Creatinine and Cystatin C in estimating Glomerular Filtration Rate in Older Adults

Utility of serum beta-trace protein as a tool for estimating residual kidney function in peritoneal dialysis patients

Determining the Glomerular Filtration Rate—An Overview

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