Mary K Robinson1, Samuel P Caudill1, David D Koch2, James Ritchie3, Glen Hortin4, John H Eckfeldt5, Sverre Sandberg6, Desmond Williams7, Gary Myers8, W Greg Miller9. 1. Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control & Prevention, Atlanta, GA, United States. 2. Grady Memorial Hospital and Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States. 3. Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States. 4. Quest Diagnostics, Cincinnati, OH, United States. 5. University of Minnesota, Department of Laboratory Medicine and Pathology Minneapolis, MN, United States. 6. Laboratory of Clinical Biochemistry, Haukeland University Hospital and the Norwegian Quality Improvement of Primary Care Laboratories, Bergen, Norway. 7. Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control & Prevention, Atlanta, GA, United States. 8. American Association for Clinical Chemistry, Washington, DC, United States. 9. Virginia Commonwealth University, Department of Pathology, Richmond, VA, United States. Electronic address: gmiller@vcu.edu.
Abstract
BACKGROUND: Adsorption of albumin onto urine collection and analysis containers may cause falsely low concentrations. METHODS: We added (125)I-labeled human serum albumin to urine and to phosphate buffered solutions, incubated them with 22 plastic container materials and measured adsorption by liquid scintillation counting. RESULTS: Adsorption of urine albumin (UA) at 5-6 mg/l was <0.9%; and at 90 mg/l was <0.4%. Adsorption was generally less at pH8 than pH5 but only 3 cases had p<0.05. Adsorption from 11 unaltered urine samples with albumin 5-333 mg/l was <0.8%. Albumin adsorption for the material with greatest binding was extrapolated to the surface areas of 100 ml and 2l collection containers, and to instrument sample cups and showed <1% change in concentration at 5 mg/l and <0.5% change at 20 mg/l or higher concentrations. Adsorption of albumin from phosphate buffered solutions (2-28%) was larger than that from urine. CONCLUSIONS: Albumin adsorption differed among urine samples and plastic materials, but the total influence of adsorption was <1% for all materials and urine samples tested. Adsorption of albumin from phosphate buffered solutions was larger than that from urine and could be a limitation for preparations used as calibrators.
BACKGROUND: Adsorption of albumin onto urine collection and analysis containers may cause falsely low concentrations. METHODS: We added (125)I-labeled humanserum albumin to urine and to phosphate buffered solutions, incubated them with 22 plastic container materials and measured adsorption by liquid scintillation counting. RESULTS: Adsorption of urine albumin (UA) at 5-6 mg/l was <0.9%; and at 90 mg/l was <0.4%. Adsorption was generally less at pH8 than pH5 but only 3 cases had p<0.05. Adsorption from 11 unaltered urine samples with albumin 5-333 mg/l was <0.8%. Albumin adsorption for the material with greatest binding was extrapolated to the surface areas of 100 ml and 2l collection containers, and to instrument sample cups and showed <1% change in concentration at 5 mg/l and <0.5% change at 20 mg/l or higher concentrations. Adsorption of albumin from phosphate buffered solutions (2-28%) was larger than that from urine. CONCLUSIONS:Albumin adsorption differed among urine samples and plastic materials, but the total influence of adsorption was <1% for all materials and urine samples tested. Adsorption of albumin from phosphate buffered solutions was larger than that from urine and could be a limitation for preparations used as calibrators.
Authors: H J Lambers Heerspink; F L Nauta; C P van der Zee; J W Brinkman; R T Gansevoort; D de Zeeuw; S J L Bakker Journal: Diabet Med Date: 2009-05 Impact factor: 4.359
Authors: W Greg Miller; David E Bruns; Glen L Hortin; Sverre Sandberg; Kristin M Aakre; Matthew J McQueen; Yoshihisa Itoh; John C Lieske; David W Seccombe; Graham Jones; David M Bunk; Gary C Curhan; Andrew S Narva Journal: Clin Chem Date: 2008-11-21 Impact factor: 8.327