title: Albumin adsorption onto surfaces of urine collection and analysis containers.
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.
authors: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control & Prevention, Atlanta, GA, United States.
authors: Mary K
authors: MK
authors: Robinson
authors: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control & Prevention, Atlanta, GA, United States.
authors: Samuel P
authors: SP
authors: Caudill
authors: Grady Memorial Hospital and Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States.
authors: David D
authors: DD
authors: Koch
authors: Emory University, Department of Pathology & Laboratory Medicine, Atlanta, GA, United States.
authors: James
authors: J
authors: Ritchie
authors: Quest Diagnostics, Cincinnati, OH, United States.
authors: Glen
authors: G
authors: Hortin
authors: University of Minnesota, Department of Laboratory Medicine and Pathology Minneapolis, MN, United States.
authors: John H
authors: JH
authors: Eckfeldt
authors: Laboratory of Clinical Biochemistry, Haukeland University Hospital and the Norwegian Quality Improvement of Primary Care Laboratories, Bergen, Norway.
authors: Sverre
authors: S
authors: Sandberg
authors: Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control & Prevention, Atlanta, GA, United States.
authors: Desmond
authors: D
authors: Williams
authors: American Association for Clinical Chemistry, Washington, DC, United States.
authors: Gary
authors: G
authors: Myers
authors: Virginia Commonwealth University, Department of Pathology, Richmond, VA, United States. Electronic address: gmiller@vcu.edu.
authors: W Greg
authors: WG
authors: Miller
mesh_terms: D000327:Adsorption; D000418:Albumins / Q000737:chemistry*; D000419:Albuminuria / Q000652:urine*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry; D012711:Serum Albumin, Radio-Iodinated / Q000652:urine; D013499:Surface Properties; D013501:Surface-Active Agents; D059349:Urine Specimen Collection / Q000295:instrumentation* / Q000379:methods
chemical_list: D000418:Albumins; D012709:Serum Albumin; D012711:Serum Albumin, Radio-Iodinated; D013501:Surface-Active Agents
keywords: Albumin adsorption; Urine albumin; Urine containers