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Nordin G.,Equalis Inc. | Dybkaer R.,Copenhagen University | Forsum U.,Linkoping University | Fuentes-Arderiu X.,Hospital Universitari Of Bellvitge | And 2 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2010

Scientists of disciplines in clinical laboratory sciences have long recognized the need for a common language for efficient and safe request of investigations, reporting of results, and communication of experience and scientific achievements. Widening the scope, most scientific disciplines, not only clinical laboratory sciences, rely to some extent on various nominal examinations, in addition to measurements. The 'International vocabulary of metrology - Basic and general concepts and associated terms' (VIM) is designed for metrology, science of measurement. The aim of the proposed vocabulary is to suggest definitions and explanations of concepts and terms related to nominal properties, i.e., properties that can be compared for identity with other properties of the same kind-of-property, but that have no magnitude. © 2010 by Walter de Gruyter. Source

Nordin G.,Equalis Inc.
Clinical Chemistry and Laboratory Medicine | Year: 2015

The term "qualitative test" is ambiguous and should not be used for nominal (classification) or ordinal (grading) tests. Characteristics for nominal and ordinal scale test results, such as traceability and uncertainty, remains to be established before general performance criteria can be agreed upon. For ordinal binary test with a quantitative back ground scale an assay could be characterized with the three quantities "C5", "C50", and "C95". The C50-value, or the equivalence point, ought to be declared by the manufacturers of diagnostic products. For the correct understanding and communication of results from ordinal and nominal tests the way of expressing the results also need to be harmonized. © 2015 by De Gruyter. Source

Topic E.,Barutanski Jarak | Nikolac N.,University of Zagreb | Panteghini M.,University of Milan | Theodorsson E.,Linkoping University | And 6 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2015

Laboratory medicine is amongst the fastest growing fields in medicine, crucial in diagnosis, support of prevention and in the monitoring of disease for individual patients and for the evaluation of treatment for populations of patients. Therefore, high quality and safety in laboratory testing has a prominent role in high-quality healthcare. Applied knowledge and competencies of professionals in laboratory medicine increases the clinical value of laboratory results by decreasing laboratory errors, increasing appropriate utilization of tests, and increasing cost effectiveness. This collective paper provides insights into how to validate the laboratory assays and assess the quality of methods. It is a synopsis of the lectures at the 15th European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Continuing Postgraduate Course in Clinical Chemistry and Laboratory Medicine entitled "How to assess the quality of your method?" (Zagreb, Croatia, 24-25 October 2015). The leading topics to be discussed include who, what and when to do in validation/verification of methods, verification of imprecision and bias, verification of reference intervals, verification of qualitative test procedures, verification of blood collection systems, comparability of results among methods and analytical systems, limit of detection, limit of quantification and limit of decision, how to assess the measurement uncertainty, the optimal use of Internal Quality Control and External Quality Assessment data, Six Sigma metrics, performance specifications, as well as biological variation. This article, which continues the annual tradition of collective papers from the EFLM continuing postgraduate courses in clinical chemistry and laboratory medicine, aims to provide further contributions by discussing the quality of laboratory methods and measurements and, at the same time, to offer continuing professional development to the attendees. Source

Antovic J.P.,Karolinska University Hospital | Skeppholm M.,Karolinska Institutet | Eintrei J.,Karolinska University Hospital | Boija E.E.,Karolinska University Hospital | And 9 more authors.
European Journal of Clinical Pharmacology | Year: 2013

Background: Dabigatran is an oral direct thrombin inhibitor for which routine laboratory monitoring is currently not recommended. However, there are situations in which measurements of the drug and its effect are desirable. We therefore compared and validated different coagulation methods for assessments of dabigatran in clinical samples in relation to measurements of plasma dabigatran, without the purpose of establishing effective and safe concentrations of dabigatran in plasma. Methods: Samples were obtained from 70 atrial fibrillation patients treated with dabigatran etexilate. Plasma concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and were compared with coagulation methods Hemoclot thrombin inhibitors (HTI) and Ecarin clotting assay (ECA), as well as with prothrombin time-international normalized ratio (PT-INR) and activated partial thromboplastin time (aPTT). Results: A wide range of dabigatran concentrations was determined by LC-MS/MS (<0.5-586 ng/mL). Correlations between LC-MS/MS results and estimated concentrations were excellent for both HTI and ECA overall (r2 = 0.97 and 0.96 respectively, p < 0.0001), but the precision and variability of these assays were not fully satisfactory in the low range of dabigatran plasma concentrations, in which ECA performed better than HTI. aPTT performed poorly, and was normal (<40 s) even with dabigatran levels of 60 ng/mL. PT-INR was normal even at supratherapeutic dabigatran concentrations. Conclusion: LC-MS/MS is the gold standard for measurements of dabigatran in plasma. Alternatively, either HTI or ECA assays may be used, but neither of these assays is dependable when monitoring low levels or to infer total absence of dabigatran. The aPTT assay is relatively insensitive to dabigatran, and normal aPTT results may be observed even with therapeutic dabigatran concentrations. © 2013 Springer-Verlag Berlin Heidelberg. Source

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