title: The reference change value: a proposal to interpret laboratory reports in serial testing based on biological variation.
abstract: BACKGROUND
  A proposal to calculate and use the reference change value (RCV) as an objective guide for interpreting the numerical results obtained in clinical laboratory serial testing is introduced in this study.
  
  
  METHODS
  A database showing the results of a compilation of 191 publications on biological variation and including information on a number of analytes provided the standardized criterion based on biology for calculating the RCVs.
  
  
  RESULTS
  For each of the 261 analytes included in the study, the RCV was determined using Harris's formula, replacing analytical imprecision with the desirable specification of analytical quality based on half the within-subject biological variation at 95% probability levels. The result is a guide for a common criterion to identify clinically significant changes in serial results.
  
  
  CONCLUSIONS
  The RCV concept is an approach that can be offered by laboratories to assess changes in serial results. The RCV data in this study are presented as a point of departure for a widely applicable objective guide to interpret changes in serial results.
authors.affiliation: Laboratoris Clínics Hospital Vall d'Hebron, Barcelona, Spain. cricos@hg.vhebron.es
authors.forename: C
authors.initials: C
authors.lastname: Ricós
authors.forename: F
authors.initials: F
authors.lastname: Cava
authors.forename: J V
authors.initials: JV
authors.lastname: García-Lario
authors.forename: A
authors.initials: A
authors.lastname: Hernández
authors.forename: N
authors.initials: N
authors.lastname: Iglesias
authors.forename: C V
authors.initials: CV
authors.lastname: Jiménez
authors.forename: J
authors.initials: J
authors.lastname: Minchinela
authors.forename: C
authors.initials: C
authors.lastname: Perich
authors.forename: M
authors.initials: M
authors.lastname: Simón
authors.forename: M V
authors.initials: MV
authors.lastname: Domenech
authors.forename: V
authors.initials: V
authors.lastname: Alvarez
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D001826:Body Fluids / Q000737:chemistry; D002624:Chemistry, Clinical / Q000592:standards* / Q000706:statistics & numerical data; D019963:Clinical Chemistry Tests / Q000592:standards / Q000706:statistics & numerical data; D002984:Clinical Laboratory Information Systems / Q000592:standards / Q000706:statistics & numerical data; D016208:Databases, Factual; D006801:Humans; D011237:Predictive Value of Tests; D011786:Quality Control; D012016:Reference Values