Michelle C Starr1, David J Askenazi2, Stuart L Goldstein3, James W MacDonald4, Theo K Bammler4, Zahra Afsharinejad4, Patrick D Brophy5, Sandra E Juul6, Dennis E Mayock6, Sangeeta R Hingorani7. 1. Division of Nephrology, Department of Pediatrics, Seattle Children's Hospital and University of Washington, 4800 Sand Point Way NE, OC.9.830, Seattle, WA, 98105, USA. michelle.starr@seattlechildrens.org. 2. Division of Pediatric Nephrology, University of Alabama at Birmingham, Birmingham, AL, USA. 3. Center for Acute Care Nephrology, University of Cincinnati College of Medicine, Cincinnati, OH, USA. 4. Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA. 5. Department of Pediatrics, University of Iowa, Carver College of Medicine, Iowa City, IA, USA. 6. Division of Neonatology, Department of Pediatrics, University of Washington, Seattle, WA, USA. 7. Division of Nephrology, Department of Pediatrics, Seattle Children's Hospital and University of Washington, 4800 Sand Point Way NE, OC.9.830, Seattle, WA, 98105, USA.
Abstract
BACKGROUND: In neonates, the validation of urinary biomarkers to diagnose acute kidney injury is a rapidly evolving field. The neonatal population poses unique challenges when assessing the collection, storage, and processing of urinary samples for biomarker analysis. Given this, establishing optimal and consistent sample processing in this population for meaningful use in ongoing clinical trials is important. METHODS: Urine from a cohort of 19 hospitalized neonatal intensive care unit patients enrolled in the Preterm Erythropoietin Neuroprotection Trial (Clinical Trial NCT01378273) was collected for biomarker analysis by indirect techniques using Fisher-brand cotton balls placed in the diapers. Fourteen urinary biomarkers were measured using commercially available kits via electrochemiluminescence on multiarray plates and compared between paired samples processed with centrifugation prior to storage versus prior to analysis. RESULTS: None of the biomarker concentrations differed between samples undergoing centrifugation prior to storage versus prior to analysis. The difference between samples was within 2% of the estimated concentration for the protein in 12 of 14 biomarkers (86%), and all paired biomarker concentrations were within 4%. The percentage error analysis did not show a difference between paired samples, with biomarker percentage errors smaller than the stated immunoassay coefficient of variance. CONCLUSIONS: The urinary concentrations of biomarkers were comparable between paired samples, demonstrating that indirectly collected neonatal urine samples do not require centrifugation after collection and before storage. The ability to use routine urine collection and storage methods to obtain samples for subsequent quantitative immunoassay analysis should facilitate studies of newborns and young children.
BACKGROUND: In neonates, the validation of urinary biomarkers to diagnose acute kidney injury is a rapidly evolving field. The neonatal population poses unique challenges when assessing the collection, storage, and processing of urinary samples for biomarker analysis. Given this, establishing optimal and consistent sample processing in this population for meaningful use in ongoing clinical trials is important. METHODS: Urine from a cohort of 19 hospitalized neonatal intensive care unit patients enrolled in the Preterm Erythropoietin Neuroprotection Trial (Clinical Trial NCT01378273) was collected for biomarker analysis by indirect techniques using Fisher-brand cotton balls placed in the diapers. Fourteen urinary biomarkers were measured using commercially available kits via electrochemiluminescence on multiarray plates and compared between paired samples processed with centrifugation prior to storage versus prior to analysis. RESULTS: None of the biomarker concentrations differed between samples undergoing centrifugation prior to storage versus prior to analysis. The difference between samples was within 2% of the estimated concentration for the protein in 12 of 14 biomarkers (86%), and all paired biomarker concentrations were within 4%. The percentage error analysis did not show a difference between paired samples, with biomarker percentage errors smaller than the stated immunoassay coefficient of variance. CONCLUSIONS: The urinary concentrations of biomarkers were comparable between paired samples, demonstrating that indirectly collected neonatal urine samples do not require centrifugation after collection and before storage. The ability to use routine urine collection and storage methods to obtain samples for subsequent quantitative immunoassay analysis should facilitate studies of newborns and young children.
Authors: Chirag R Parikh; Isabel Butrymowicz; Angela Yu; Vernon M Chinchilli; Meyeon Park; Chi-Yuan Hsu; W Brian Reeves; Prasad Devarajan; Paul L Kimmel; Edward D Siew; Kathleen D Liu Journal: Am J Kidney Dis Date: 2013-11-05 Impact factor: 8.860
Authors: Meredith P Schuh; Edward Nehus; Qing Ma; Christopher Haffner; Michael Bennett; Catherine D Krawczeski; Prasad Devarajan Journal: Am J Kidney Dis Date: 2015-05-29 Impact factor: 8.860
Authors: A H Sohn; D O Garrett; R L Sinkowitz-Cochran; L A Grohskopf; G L Levine; B H Stover; J D Siegel; W R Jarvis Journal: J Pediatr Date: 2001-12 Impact factor: 4.406