title: Agreement between methods.
abstract: Before new tests are implemented, it is important to compare their results with those of other measurement methods that are already in use. In the determination of this so-called agreement between methods, one may choose between several statistical approaches. The correlation coefficient is a popular approach to determine the agreement between measurement methods. It is easy to calculate, but has important limitations: it does not provide any information on the type of association and it is extremely sensitive to the range of values within the study. Finally, a correlation coefficient does not reveal whether any difference between two measurements is systematic or random. Therefore, it is highly preferable to use Bland-Altman plots instead, as these reveal both systematic and random errors. Bland-Altman plots are also preferable in case of repeated measurements and calibrations.
authors.affiliation: ERA-EDTA Registry, Department of Medical Informatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Karlijn J
authors.initials: KJ
authors.lastname: van Stralen
authors.forename: Kitty J
authors.initials: KJ
authors.lastname: Jager
authors.forename: Carmine
authors.initials: C
authors.lastname: Zoccali
authors.forename: Friedo W
authors.initials: FW
authors.lastname: Dekker
mesh_terms: D003401:Creatine / Q000493:pharmacokinetics; D005919:Glomerular Filtration Rate; D006801:Humans; D007444:Inulin / Q000493:pharmacokinetics; D008722:Methods; D015203:Reproducibility of Results; D013223:Statistics as Topic
chemical_list: D007444:Inulin; D003401:Creatine