Browsing Bergen Open Research Archive by Author "Kristoffersen, Ann-Helen"
Now showing items 1-7 of 7
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The European Biological Variation Study (EuBIVAS): Biological Variation Data for Coagulation Markers Estimated by a Bayesian Model
Aarsand, Aasne K.; Kristoffersen, Ann-Helen; Sandberg, Sverre; Støve, Bård; Coşkun, Abdurrahman; Fernandez-Calle, Pilar; Díaz-Garzón, Jorge; Guerra, Elena; Ceriotti, Ferruccio; Jonker, Niels; Røraas, Thomas; Carobene, Anna (Journal article; Peer reviewed, 2021)Background For biological variation (BV) data to be safely used, data must be reliable and relevant to the population in which they are applied. We used samples from the European Biological Variation Study (EuBIVAS) to ... -
How to conduct External Quality Assessment Schemes for the pre-analytical phase?
Kristensen, Gunn Berit Berge; Aakre, Kristin; Kristoffersen, Ann-Helen; Sandberg, Sverre (Peer reviewed; Journal article, 2014)In laboratory medicine, several studies have described the most frequent errors in the different phases of the total testing process, and a large proportion of these errors occur in the pre-analytical phase. Schemes for ... -
Impact of different preanalytical conditions on results of lupus anticoagulant tests
Kristoffersen, Ann-Helen; Jansrud, Ida; Vannes, Solveig; Åsberg, Arne; Aakre, Kristin Moberg (Peer reviewed; Journal article, 2019)Introduction: The currently recommended preanalytical conditions for lupus anticoagulant (LA) analysis require analyzing samples in fresh or freshly frozen platelet‐poor plasma. The aim of this study was to evaluate whether ... -
A national surveillance program for evaluating new reagent lots in medical laboratories
Solsvik, Anne Elisabeth; Kristoffersen, Ann-Helen; Sandberg, Sverre; Gidske, Gro; Stavelin, Anne; Eikeland, Joakim; Amundsen, Erik Koldberg (Journal article; Peer reviewed, 2022)Objectives Differences between laboratory results attributable to the use of different reagent lots can potentially affect the diagnosis and monitoring of patients. To minimize patient risks, all laboratories should verify ... -
Pre-analytical practices for routine coagulation tests in European laboratories. A collaborative study from the European Organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM)
Kristoffersen, Ann-Helen; Stavelin, Anne; Ajzner, Éva; Kristensen, Gunn Berit Berge; Sandberg, Sverre; van Blerk, Marjan; Kitchen, Steve; Kesseler, Dagmar; Woods, Timothy A.L.; Meijer, Piet (Peer reviewed; Journal article, 2019)Background: Correct handling and storage of blood samples for coagulation tests are important to assure correct diagnosis and monitoring. The aim of this study was to assess the pre-analytical practices for routine coagulation ... -
Quality of warfarin therapy and quality of life are improved by self-management for two years
Sølvik, Una Ørvim; Løkkebø, Elisabeth Sellevoll; Kristoffersen, Ann-Helen; Brodin, Ellen Elisabeth; Averina, Maria; Sandberg, Sverre (Peer reviewed; Journal article, 2019)Background: Studies from several countries show that self-management of vitamin K antagonist (e.g., warfarin) therapy reduce the risk of complications compared with conventional management. Objectives: The aim of this study ... -
Serum or Plasma for Quantification of Direct Oral Anticoagulants?
Aakerøy, Rachel; Stokes, Charlotte Lorentze; Tomic, Marija; Hegstad, Solfrid; Kristoffersen, Ann-Helen; Ellekjær, Hanne; Schjøtt, Jan Didrik; Spigset, Olav; Helland, Arne (Journal article; Peer reviewed, 2022)Background: Direct oral anticoagulants are increasingly replacing vitamin K antagonists for prevention of stroke in patients with atrial fibrillation, partly owing to the lack of a need for routine monitoring. Therapeutic ...