Year: 2016
Type: article
Abstract: BACKGROUND: Although stored urine samples are often used in biomarker studies focused on acute and chronic kidney disease, how storage time impacts biomarker levels is not well understood. METHODS: 866 subjects enrolled in the NIDDK-sponsored ASsessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study were included. Samples were processed under standard conditions and stored at -70°C until analyzed. Kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), and liver fatty acid binding protein (L-FABP) were measured in urine samples collected during the index hospitalization or an outpatient visit 3 months later. Mixed effects models were used to determine the effect of storage time on biomarker levels and stratified by visit. RESULTS: Median storage was 17.8 months (25-75% IQR 10.6-23.7) for samples from the index hospitalization and 14.6 months (IQR 7.3-20.4) for outpatient samples. In the mixed effects models, the only significant association between storage time and biomarker concentration was for KIM-1 in outpatient samples, where each month of storage was associated with a 1.7% decrease (95% CI -3% to -0.3%). There was no relationship between storage time and KIM-1 levels in samples from the index hospitalization. CONCLUSION: There was no significant impact of storage time over a median of 18 months on urine KIM-1, NGAL, IL-18 or L-FABP in hospitalized samples; a statistically significant effect towards a decrease over time was noted for KIM-1 in outpatient samples. Additional studies are needed to determine whether longer periods of storage at -70°C systematically impact levels of these analytes.
Source: PLoS ONE
Authors: Kathleen D. Liu, Edward D. Siew, W. Brian Reeves, Jonathan Himmelfarb, Alan S. Go, Chi-yuan Hsu, Michael R. Bennett, Prasad Devarajan, T. Alp Ikizler, James S. Kaufman, Paul L. Kimmel, Vernon M. Chinchilli, Chirag R. Parikh, for the ASSESS-AKI Study Investigators
Institutions: University of California, San Francisco, Vanderbilt University Medical Center, Pennsylvania State University, Penn State Milton S. Hershey Medical Center, University of Washington, Kaiser Permanente, Kaiser Permanente Northern California, Cincinnati Children's Hospital Medical Center, VA NY Harbor Healthcare System, New York University, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Yale University
Language: English
Topic: Acute Kidney Injury Research
Subfield: Nephrology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,382
Funders: U.S. Department of Health and Human Services, Yale University, Kaiser Permanente, Vanderbilt University, University of Pennsylvania, University of Washington, Pennsylvania State University, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, National Center for Research Resources
Awards: Clinical and Translational Science Institute, G1758742817, Genetic Determinants of Outcomes in Acute Kidney Injury, Acute Kidney Injury: A Novel Risk Factor for Cardiovascular Events, Data Coordinating Center for the Natural History of AKI Consortium, Critical Translational Studies in Pediatric Nephrology, G5762447951, Prospective Evaluation of Acute Kidney Injury II (PEAK-2), G653053388, G6796483150, Progression of Acute Kidney Injury to Chronic Kidney Disease, Impact of Acute Kidney Injury on Kidney Disease Progression
OpenAlex ID: W2545753519