title: A reference system for urinary albumin: current status.
abstract: BACKGROUND
  Increased urinary excretion of albumin reflects kidney damage and is a recognized risk factor for progression of renal and cardiovascular disease. Considerable inter-method differences have been reported for both albumin and creatinine measurement results, and therefore the albumin-to-creatinine ratio. Measurement accuracy is unknown and there are no independent reference measurement procedures for albumin and no reference materials for either measurand in urine.
  
  
  METHODS
  The National Kidney Disease Education Program (NKDEP) Laboratory Working Group and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) have initiated joint projects to facilitate standardization of urinary albumin and creatinine measurement.
  
  
  RESULTS
  A candidate LC-MS/MS reference measurement procedure for urinary albumin and candidate reference materials for urinary albumin and creatinine has been developed. The status of validations of these reference system components is reported.
  
  
  CONCLUSIONS
  The development of certified reference materials and reference measurement procedures for urinary albumin will enable standardization of this important measurand.
authors.affiliation: Mayo Clinic Renal Function Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic Division of Nephrology and Hypertension, Department of Internal Medicine, Rochester, MN 55905, USA. Lieske.John@mayo.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Lieske
authors.forename: Olga
authors.initials: O
authors.lastname: Bondar
authors.forename: W Greg
authors.initials: WG
authors.lastname: Miller
authors.forename: Lorin M
authors.initials: LM
authors.lastname: Bachmann
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Narva
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Itoh
authors.forename: Ingrid
authors.initials: I
authors.lastname: Zegers
authors.forename: Heinz
authors.initials: H
authors.lastname: Schimmel
authors.forename: Karen
authors.initials: K
authors.lastname: Phinney
authors.forename: David M
authors.initials: DM
authors.lastname: Bunk
mesh_terms: D000418:Albumins / Q000032:analysis / Q000592:standards*; D002853:Chromatography, Liquid / Q000592:standards; D019963:Clinical Chemistry Tests / Q000592:standards*; D003404:Creatinine / Q000592:standards* / Q000652:urine; D006801:Humans; D007753:Laboratories / Q000592:standards*; D012015:Reference Standards; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D000418:Albumins; D003404:Creatinine