title: LEGO plot for simultaneous application of multiple quality requirements during trueness verification of quantitative laboratory tests.
abstract: BACKGROUND
  We developed a two-dimensional plot for viewing trueness that takes into account potential shift and variable quality requirements to verify trueness using certified reference material (CRM).
  
  
  METHODS
  Glucose, total cholesterol (TC), and creatinine levels were determined by two kinds of assay in two levels of a CRM. Available quality requirements were collected, codified, and sorted in an ascending order in the plot's header row. Centering on the mean of measured values from CRM, the "mean ± US CLIA '88 allowable total error" was located in the header of the leftmost and rightmost columns. Twenty points were created in intervening columns as potential shifts. Uncertainties were calculated according to regression between certified values and uncertainties of CRM, and positioned in the corresponding columns. Cells were assigned different colors where column and row intersected based on comparison of the 95% confidence interval of the percentage bias with each quality requirement.
  
  
  RESULTS
  A glucose assay failed to meet the highest quality criteria, for which shift of +0.13-0.14 mmol/l was required. A TC assay met the quality requirement and a shift of ±0.03 mmol/l was tolerable. A creatinine assay also met the quality requirement but any shift was not tolerable.
  
  
  CONCLUSIONS
  The plot provides a systematic view of the trueness of quantitative laboratory tests.
authors.affiliation: Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea; Catholic Laboratory Development and Evaluation Center, Clinical Research Coordinating Center, Catholic Medical Center, Seoul, Republic of Korea.
authors.forename: Hae-il
authors.initials: HI
authors.lastname: Park
authors.forename: Hyojin
authors.initials: H
authors.lastname: Chae
authors.forename: Myungshin
authors.initials: M
authors.lastname: Kim
authors.forename: Jehoon
authors.initials: J
authors.lastname: Lee
authors.forename: Yonggoo
authors.initials: Y
authors.lastname: Kim
mesh_terms: D015982:Bias; D001681:Biological Assay; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D019411:Clinical Laboratory Techniques / Q000379:methods* / Q000592:standards*; D003404:Creatinine / Q000097:blood; D006801:Humans; D011786:Quality Control; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D002784:Cholesterol; D003404:Creatinine
keywords: bias; quality requirement; shift; trueness; verification