title: Sample matrix is critical in the evaluation of a dry-slide bromocresol green method for human albumin.
abstract: BACKGROUND
  A dry-slide bromocresol green method for serum albumin consistently demonstrated negative bias in a proficiency testing scheme, particularly at low albumin concentrations.
  
  
  RESULTS
  Albumin was measured using both a dry-slide method and an immunonephelometric method in patient serum samples and external quality assessment samples. Results obtained using the dry-slide method were lower than those obtained using immunonephelometry (mean bias--1.0 g/L, P=0.0039), but this difference was exaggerated in the quality assessment samples. In three other albumin preparations with assigned concentrations, recovery with the dry-slide method decreased upon dilution of the matrix.
  
  
  CONCLUSIONS
  Our results suggest that apparent under-recovery of albumin using this technology is probably due to the diffusive properties of the quality assessment sample matrix.
authors.affiliation: Department of Clinical Biochemistry, East Kent Hospitals NHS Trust, Kent and Canterbury Hospital, UK.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Payn
authors.forename: David
authors.initials: D
authors.lastname: Lawrence
authors.forename: Roger
authors.initials: R
authors.lastname: Willis
authors.forename: Edmund J
authors.initials: EJ
authors.lastname: Lamb
mesh_terms: D015982:Bias; D001800:Blood Specimen Collection; D001961:Bromcresol Green; D004058:Diffusion; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D011786:Quality Control; D012709:Serum Albumin / Q000032:analysis*
chemical_list: D012709:Serum Albumin; D001961:Bromcresol Green