Routine internal- and external-quality control data in clinical laboratories for estimating measurement and diagnostic uncertainty using GUM principles
2012 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, Vol. 72, no 3, 212-220 p.Article in journal (Refereed) Published
Healthcare laboratories are increasingly joining into larger laboratory organizations encompassing several physical laboratories. This caters for important new opportunities for re-defining the concept of a laboratory to encompass all laboratories and measurement methods measuring the same measurand for a population of patients. In order to make measurement results, comparable bias should be minimized or eliminated and measurement uncertainty properly evaluated for all methods used for a particular patient population. The measurement as well as diagnostic uncertainty can be evaluated from internal and external quality control results using GUM principles. In this paper the uncertainty evaluations are described in detail using only two main components, within-laboratory reproducibility and uncertainty of the bias component according to a Nordtest guideline. The evaluation is exemplified for the determination of creatinine in serum for a conglomerate of laboratories both expressed in absolute units (mu mol/L) and relative (%). An expanded measurement uncertainty of 12 mu mol/L associated with concentrations of creatinine below 120 mu mol/L and of 10% associated with concentrations above 120 mu mol/L was estimated. The diagnostic uncertainty encompasses both measurement uncertainty and biological variation, and can be estimated for a single value and for a difference. This diagnostic uncertainty for the difference for two samples from the same patient was determined to be 14 mu mol/L associated with concentrations of creatinine below 100 mu mol/L and 14 % associated with concentrations above 100 mu mol/L.
Place, publisher, year, edition, pages
Informa Healthcare , 2012. Vol. 72, no 3, 212-220 p.
Metrology, GUM, measurement uncertainty, quality control, creatinine, analysis, bias, precision
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-77092DOI: 10.3109/00365513.2011.649015ISI: 000302562700005OAI: oai:DiVA.org:liu-77092DiVA: diva2:524965
Funding Agencies|European Community|217257|2012-05-042012-05-042012-05-04