| 1. |
- Oosterhuis, Wytze P., et al.
(författare)
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The use of error and uncertainty methods in the medical laboratory
- 2018
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:2, s. 209-219
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Tidskriftsartikel (refereegranskat)abstract
- Error methods - compared with uncertainty methods - offer simpler, more intuitive and practical procedures for calculating measurement uncertainty and conducting quality assurance in laboratory medicine. However, uncertainty methods are preferred in other fields of science as reflected by the guide to the expression of uncertainty in measurement. When laboratory results are used for supporting medical diagnoses, the total uncertainty consists only partially of analytical variation. Biological variation, pre- and postanalytical variation all need to be included. Furthermore, all components of the measuring procedure need to be taken into account. Performance specifications for diagnostic tests should include the diagnostic uncertainty of the entire testing process. Uncertainty methods may be particularly useful for this purpose but have yet to show their strength in laboratory medicine. The purpose of this paper is to elucidate the pros and cons of error and uncertainty methods as groundwork for future consensus on their use in practical performance specifications. Error and uncertainty methods are complementary when evaluating measurement data.
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| 2. |
- Coskun, Abdurrahman, et al.
(författare)
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Measurement uncertainty for practical use
- 2022
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Ingår i: Clinica Chimica Acta. - : ELSEVIER. - 0009-8981 .- 1873-3492. ; 531, s. 352-360
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Tidskriftsartikel (refereegranskat)abstract
- Uncertainty is an inseparable part of all kinds of measurements performed in clinical laboratories. Accreditation standards including the ISO/IEC 17025:2017 and ISO 15189:2012 require that laboratories have routines for calculating the measurement uncertainty of reported results. Various guidelines such as CLSI EP29, Nordest 537, and ISO 20914:2019 have proposed methods for this purpose. However, due to the conceived complexity of the proposed calculation methods, these guidelines have not been generally and effectively applied in clinical laboratories. High workload and measurand heterogeneity favor a pragmatic utilitarian approach. The purpose of this paper is to describe such an approach, including its advantages and disadvantages. Measurement uncertainty should include the most influential factors affecting patients test results. Since patients samples for the same measurand can be analyzed in one laboratory or several laboratories using different measuring systems, the measurement uncertainty should be calculated using results obtained from analyzing the same internal quality control material if commutable or patients pooled/split samples.
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| 3. |
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| 4. |
- Oosterhuis, Wytze P., et al.
(författare)
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Performance specifications for sodium should not be based on biological variation
- 2023
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Ingår i: Clinica Chimica Acta. - : ELSEVIER. - 0009-8981 .- 1873-3492. ; 540
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Tidskriftsartikel (refereegranskat)abstract
- When increasing the quality in clinical laboratories by decreasing measurement uncertainty, reliable methods are needed not only to quantify the performance of measuring systems, but also to set goals for the performance. Sigma metrics used in medical laboratories for documenting and expressing levels of performance, are evidently totally dependent on the "total permissible error" used in the formulas. Although the conventional biological variation (BV) based model for calculation of the permissible (or allowable) total error is commonly used, it has been shown to be flawed. Alternative methods are proposed, mainly also based on the within-subject BV. Measurement uncertainty models might offer an alternative to total error models. Defining the limits for analytical quality still poses a challenge in both models. The aim of the present paper is to critically discuss current methods for establishing performance specifica-tions by using the measurement of sodium concentrations in plasma or serum. Sodium can be measured with high accuracy but fails by far to meet conventional performance specifications based on BV. Since the use of sodium concentrations is well established for supporting clinical care, we question the concept that quality criteria for sodium and similar analytes that are under strict homeostatic control are best set by biology.
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| 5. |
- Oosterhuis, Wytze P., et al.
(författare)
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Total error vs. measurement uncertainty: revolution or evolution?
- 2016
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 54:2, s. 235-239
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Tidskriftsartikel (refereegranskat)abstract
- The first strategic EFLM conference "Defining analytical performance goals, 15 years after the Stockholm Conference" was held in the autumn of 2014 in Milan. It maintained the Stockholm 1999 hierarchy of performance goals but rearranged them and established five task and finish groups to work on topics related to analytical performance goals including one on the "total error" theory. Jim Westgard recently wrote a comprehensive overview of performance goals and of the total error theory critical of the results and intentions of the Milan 2014 conference. The "total error" theory originated by Jim Westgard and co-workers has a dominating influence on the theory and practice of clinical chemistry but is not accepted in other fields of metrology. The generally accepted uncertainty theory, however, suffers from complex mathematics and conceived impracticability in clinical chemistry. The pros and cons of the total error theory need to be debated, making way for methods that can incorporate all relevant causes of uncertainty when making medical diagnoses and monitoring treatment effects. This development should preferably proceed not as a revolution but as an evolution.
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| 6. |
- Watson, Ian D., et al.
(författare)
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European views on patients directly obtaining their laboratory test results
- 2015
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 53:12, s. 1961-1966
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Tidskriftsartikel (refereegranskat)abstract
- Background: Medicine is a highly professionalized endeavour, by tradition centred on the authority of physicians. Better education and the advent of the information age cater for increased demands on society in general and on health care in particular to enable people to make informed decisions regarding themselves. Participation in medical decisions requires informed knowledge which is hard to obtain without substantial and time consuming professional help. Methods: We performed a survey amongst the member organizations of European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) in order to investigate the recognition and preparedness of providing help to patients in interpreting their laboratory results. Results: Out of 40 EFLM Member Societies, 27 sent their responses to the survey. In most cases the first line delivery of laboratory results to physicians is by computer link (63%). Patients receive their laboratory results on demand from their physician in 60% of cases. However, 34% of laboratory specialists showed a negative attitude for delivering laboratory results to patients. Yet, in 48% of countries 1-5 patients per day ask a laboratory specialist about the significance of laboratory results outside the reference range. When patients are informed about the purpose of laboratory testing, they seek information primarily from their physician, followed by the internet and the Specialist in Laboratory Medicine. Conclusions: Changing practices increasingly enabling patient access to their records are on the increase facilitated by recent innovations in information technologies. Successful transfer of some of the responsibilities of physicians, demands a mutual triangular dialogue between the patient, their physician and laboratory medicine.
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