Analytical characteristics of a biomarker-based risk assessment test for acute kidney injury (AKI).

BackgroundAcute kidney injury (AKI) is associated with increased mortality, morbidity, hospital length of stay, and costs. A quantitative urine test is available to assess the risk of developing AKI by measuring the concentrations of two protein biomarkers, TIMP-2 and IGFBP-7. The NephroCheck Test combines these concentrations into an AKIRisk Score. The purpose of this study is to characterize the analytical performance characteristics of the AKIRisk Score.MethodsLinearity and analytical sensitivity were evaluated by following Clinical Laboratory Standards Institute (CLSI) EP06-A and EP17-A, respectively. Precision was evaluated by testing clinical samples and examining the repeatability of test results. Potential interference was evaluated for endogenous and exogenous substances. Sample stability was examined at room temperature and at 2-8°C, as well as the effect of sample centrifugation temperature on test results.ResultsThe AKIRisk Score exhibits approximately 10% coefficient of variation (CV) at the recommended cutoff value of 0.3 and the limit of quantitation (LoQ) was 0.002. Only albumin, bilirubin (conjugated), and methylene blue interfered with test results, at concentrations exceeding 1250 mg/L, 72 mg/L, and 0.49 mg/L, respectively. AKIRisk Score results were stable for 6h at room temperature, 24h refrigerated, and not impacted by sample centrifugation temperature.ConclusionsOur studies demonstrate that the AKIRisk Score has robust analytical performance, good precision, minimal analytical interference, acceptable sensitivity, and excellent sample stability

Transport-Kinetic Processes and Surface Chemistry in Biosensor Design

124 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.Finally, sample mixing is examined as a potential method to improve the performance of microfluidic biosensors. We attempt to mix sections of the sample solution where the analyte concentration is high with other sections where it is low, and thereby reduce the sensor response time when the detection kinetics are diffusion-limited. A serpentine micromixer, originally designed to mix two fluids in bulk solution via "chaotic advection," is used to mix the sample as it passes through a surface plasmon resonance biosensor. These experiments indicate that such "solution-based" mixing strategies can be effective in microfluidic biosensors.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Transport-Kinetic Processes and Surface Chemistry in Biosensor Design

124 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.Finally, sample mixing is examined as a potential method to improve the performance of microfluidic biosensors. We attempt to mix sections of the sample solution where the analyte concentration is high with other sections where it is low, and thereby reduce the sensor response time when the detection kinetics are diffusion-limited. A serpentine micromixer, originally designed to mix two fluids in bulk solution via "chaotic advection," is used to mix the sample as it passes through a surface plasmon resonance biosensor. These experiments indicate that such "solution-based" mixing strategies can be effective in microfluidic biosensors.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Analytical characteristics of a biomarker-based risk assessment test for acute kidney injury (AKI).

BackgroundAcute kidney injury (AKI) is associated with increased mortality, morbidity, hospital length of stay, and costs. A quantitative urine test is available to assess the risk of developing AKI by measuring the concentrations of two protein biomarkers, TIMP-2 and IGFBP-7. The NephroCheck Test combines these concentrations into an AKIRisk Score. The purpose of this study is to characterize the analytical performance characteristics of the AKIRisk Score.MethodsLinearity and analytical sensitivity were evaluated by following Clinical Laboratory Standards Institute (CLSI) EP06-A and EP17-A, respectively. Precision was evaluated by testing clinical samples and examining the repeatability of test results. Potential interference was evaluated for endogenous and exogenous substances. Sample stability was examined at room temperature and at 2-8°C, as well as the effect of sample centrifugation temperature on test results.ResultsThe AKIRisk Score exhibits approximately 10% coefficient of variation (CV) at the recommended cutoff value of 0.3 and the limit of quantitation (LoQ) was 0.002. Only albumin, bilirubin (conjugated), and methylene blue interfered with test results, at concentrations exceeding 1250 mg/L, 72 mg/L, and 0.49 mg/L, respectively. AKIRisk Score results were stable for 6h at room temperature, 24h refrigerated, and not impacted by sample centrifugation temperature.ConclusionsOur studies demonstrate that the AKIRisk Score has robust analytical performance, good precision, minimal analytical interference, acceptable sensitivity, and excellent sample stability