title: A new general regression-based approach for method comparison studies.
abstract: BACKGROUND
  A scatter plot combined with correlation and regression analysis to assess the agreement between analytical methods that measure the same quantity has a long tradition in clinical chemistry. However, only when linearity is absolute this approach may be useful to estimate whether the methods under comparison produce the same errors in measurement. The aim of this study is to provide a new original regression-based tool which does not suffer from the problems of the classical regression/correlation method and that is also easy to use and to interpret.
  
  
  METHODS
  To evaluate the performance of the new method, the results of some analytical determinations were compared by the new procedure, the Bland-Altman test, Passing-Bablok regression and Mountain plot.
  
  
  RESULTS
  All the tests used to compare the data allowed superimposable interpretations, both when methods under comparison were in agreement and in disagreement.
  
  
  CONCLUSIONS
  The understanding of the new test is truly intuitive and it is reduced to the appraisal of how much the equation of the best-fit line (Y=X) is able to predict the value of the Y. The goodness of this prediction can be evaluated by the coefficient of determination, whose value is closely connected to the differences between the methods under comparison. The result of our simulation is that quite high agreement between the methods occurs for determination coefficient equal or greater than 0.98.
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Sassari, Italy. salvatore.sotgia@gmail.com
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sotgia
authors.forename: Angelo
authors.initials: A
authors.lastname: Zinellu
authors.forename: Gerard Aime
authors.initials: GA
authors.lastname: Pinna
authors.forename: Luca
authors.initials: L
authors.lastname: Deiana
authors.forename: Ciriaco
authors.initials: C
authors.lastname: Carru
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D019963:Clinical Chemistry Tests / Q000592:standards / Q000706:statistics & numerical data; D019075:Electrophoresis, Capillary; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D006801:Humans; D015592:Immunoradiometric Assay; D020097:Natriuretic Peptide, Brain / Q000032:analysis*; D012044:Regression Analysis
chemical_list: C487735:dimethylarginine; D020097:Natriuretic Peptide, Brain; D001120:Arginine