title: An approach for estimating measurement uncertainty in medical laboratories using data from long-term quality control and external quality assessment schemes.
abstract: BACKGROUND
  The present study was prompted by the ISO 15189 requirements that medical laboratories should estimate measurement uncertainty (MU).
  
  
  METHODS
  The method used to estimate MU included the: a) identification of quantitative tests, b) classification of tests in relation to their clinical purpose, and c) identification of criteria to estimate the different MU components. Imprecision was estimated using long-term internal quality control (IQC) results of the year 2016, while external quality assessment schemes (EQAs) results obtained in the period 2015-2016 were used to estimate bias and bias uncertainty.
  
  
  RESULTS
  A total of 263 measurement procedures (MPs) were analyzed. On the basis of test purpose, in 51 MPs imprecision only was used to estimate MU; in the remaining MPs, the bias component was not estimable for 22 MPs because EQAs results did not provide reliable statistics. For a total of 28 MPs, two or more MU values were calculated on the basis of analyte concentration levels. Overall, results showed that uncertainty of bias is a minor factor contributing to MU, the bias component being the most relevant contributor to all the studied sample matrices.
  
  
  CONCLUSIONS
  The model chosen for MU estimation allowed us to derive a standardized approach for bias calculation, with respect to the fitness-for-purpose of test results. Measurement uncertainty estimation could readily be implemented in medical laboratories as a useful tool in monitoring the analytical quality of test results since they are calculated using a combination of both the long-term imprecision IQC results and bias, on the basis of EQAs results.
authors.affiliation: .
authors.forename: Andrea
authors.initials: A
authors.lastname: Padoan
authors.affiliation: .
authors.forename: Giorgia
authors.initials: G
authors.lastname: Antonelli
authors.affiliation: .
authors.forename: Ada
authors.initials: A
authors.lastname: Aita
authors.affiliation: .
authors.forename: Laura
authors.initials: L
authors.lastname: Sciacovelli
authors.affiliation: .
authors.forename: Mario
authors.identifier: http://orcid.org/0000-0002-0270-1711
authors.initials: M
authors.lastname: Plebani
mesh_terms: D000068:Accreditation; D019411:Clinical Laboratory Techniques / Q000592:standards*; D017408:Guidelines as Topic; D007755:Laboratories, Hospital / Q000592:standards*; D011786:Quality Control; D035501:Uncertainty
keywords: ISO 15189; external quality assessment schemes (EQAs); internal quality controls (IQC); measurement procedures (MPs); measurement uncertainty (MU); medical laboratory accreditation