title: Current issues in measurement and reporting of urinary albumin excretion.
abstract: BACKGROUND
  Urinary excretion of albumin indicates kidney damage and is recognized as a risk factor for progression of kidney disease and cardiovascular disease. The role of urinary albumin measurements has focused attention on the clinical need for accurate and clearly reported results. The National Kidney Disease Education Program and the IFCC convened a conference to assess the current state of preanalytical, analytical, and postanalytical issues affecting urine albumin measurements and to identify areas needing improvement.
  
  
  BACKGROUND
  The chemistry of albumin in urine is incompletely understood. Current guidelines recommend the use of the albumin/creatinine ratio (ACR) as a surrogate for the error-prone collection of timed urine samples. Although ACR results are affected by patient preparation and time of day of sample collection, neither is standardized. Considerable intermethod differences have been reported for both albumin and creatinine measurement, but trueness is unknown because there are no reference measurement procedures for albumin and no reference materials for either analyte in urine. The recommended reference intervals for the ACR do not take into account the large intergroup differences in creatinine excretion (e.g., related to differences in age, sex, and ethnicity) nor the continuous increase in risk related to albumin excretion.
  
  
  CONCLUSIONS
  Clinical needs have been identified for standardization of (a) urine collection methods, (b) urine albumin and creatinine measurements based on a complete reference system, (c) reporting of test results, and (d) reference intervals for the ACR.
authors.affiliation: Department of Pathology, Virginia Commonwealth University, Richmond, VA, USA. gmiller@vcu.edu
authors.forename: W Greg
authors.initials: WG
authors.lastname: Miller
authors.forename: David E
authors.initials: DE
authors.lastname: Bruns
authors.forename: Glen L
authors.initials: GL
authors.lastname: Hortin
authors.forename: Sverre
authors.initials: S
authors.lastname: Sandberg
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Aakre
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McQueen
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Itoh
authors.forename: John C
authors.initials: JC
authors.lastname: Lieske
authors.forename: David W
authors.initials: DW
authors.lastname: Seccombe
authors.forename: Graham
authors.initials: G
authors.lastname: Jones
authors.forename: David M
authors.initials: DM
authors.lastname: Bunk
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Narva
mesh_terms: D000419:Albuminuria / Q000175:diagnosis* / Q000652:urine*; D002853:Chromatography, Liquid; D003124:Colorimetry; D003404:Creatinine / Q000652:urine; D006801:Humans; D007118:Immunoassay; D012680:Sensitivity and Specificity; D013053:Spectrophotometry
chemical_list: D003404:Creatinine