Abstract
Objectives
Accurate prothrombin time international normalized ratio (INR) results are essential for safe anticoagulation treatment. Patients are treated both in primary and secondary healthcare, therefore equivalence of INR results from point-of-care (POC) and hospital measurement procedures (MPs) are important. It is not possible to evaluate this equivalence in traditional external quality assessment (EQA). The aim of this paper is to describe a special quality assurance system consisting of three different EQA schemes to monitor the harmonization of INR results in Norway.
Methods
The EQA scheme for hospital laboratories uses commutable control materials and evaluates participant performance and the equivalence of hospital MPs. The EQA scheme for primary healthcare laboratories uses non-commutable control materials and evaluates participant performance. A third EQA scheme for selected primary healthcare laboratories uses native patient split samples and evaluates the equivalence between POC and hospital MPs.
Results
The relationship between the three EQA schemes is presented. The split sample EQA scheme provides a link between the hospital scheme and the scheme for primary healthcare. Results from 2017 to 2022 are presented for all three schemes. When aberrant EQA results occur Noklus takes actions to be able to have a sustainable equivalence between INR results.
Conclusions
All three EQA schemes are important for monitoring the harmonization of INR results in Norway. This quality assurance system, including help and guidance of the participants, will reduce the risk of harm to patients due to non-equivalence of results from different MPs.
-
Research funding: No funding outside Noklus.
-
Author contributions: All 5 authors meet all 4 criteria of authorship: 1. Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; and 2. Drafting the work or revising it critically for important intellectual content; and 3. Final approval of the version to be published; and 4. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
-
Competing interests: Authors state no conflict of interest.
-
Informed consent: Not applicable.
-
Ethical approval: Not applicable.
References
1. Riva, N, Ageno, W. Pros and cons of vitamin K antagonists and non-vitamin K antagonist oral anticoagulants. Semin Thromb Hemostasis 2015;41:178–87. https://doi.org/10.1055/s-0035-1544231.Search in Google Scholar PubMed
2. Perry, DJ, Fitzmaurice, DA, Kitchen, S, Mackie, IJ, Mallett, S. Point-of-care testing in haemostasis. Br J Haematol 2010;150:501–14. https://doi.org/10.1111/j.1365-2141.2010.08223.x.Search in Google Scholar PubMed
3. Poller, L. International normalized ratios (INR): the first 20 years. J Thromb Haemostasis 2004;2:849–60. https://doi.org/10.1111/j.1538-7836.2004.00775.x.Search in Google Scholar PubMed
4. WHO. Expert committee on biological standardization – guidelines for thromboplastins and plasma used to control oral anticoagulant therapy with vitamin K antagonists. Geneva: World Health Organization; 2013, Techical Report Series No 979, 62nd Report.Search in Google Scholar
5. CLSI. Procedures for validation of INR and local calibration of PT/INR systems; approved guideline. Wayne, Pennsylvania, USA: Clinical and Laboratory Standards Institute; 2005, CLSI document H54-A.Search in Google Scholar
6. Lindahl, TL, Egberg, N, Hillarp, A, Odegaard, OR, Edlund, B, Svensson, J, et al.. INR calibration of Owren-type prothrombin time based on the relationship between PT% and INR utilizing normal plasma samples. Thromb Haemostasis 2004;91:1223–31. https://doi.org/10.1160/th03-07-0456.Search in Google Scholar PubMed
7. CLSI. Point-of-care coagulation testing and anticoagulation monitoring, 2nd ed. USA: Clinical and Laboratory Standards Institute; 2020, CLSI guideline POCT14.Search in Google Scholar
8. ISO17511. In vitro diagnostic medical devices – requirements for establishing metrological traceability of values assigned to calibrators, trueness control materials and human samples, 2nd ed. Geneva, Switzerland: International Organization for Standardization; 2020.Search in Google Scholar
9. Stavelin, A, Petersen, PH, Solvik, UO, Sandberg, S. External quality assessment of point-of-care methods: model for combined assessment of method bias and single-participant performance by the use of native patient samples and noncommutable control materials. Clin Chem 2013;59:363–71. https://doi.org/10.1373/clinchem.2012.191957.Search in Google Scholar PubMed
10. ISO15189. Medical laboratories – particular requirements for quality and competence. Geneva, Switzerland: International Organization for Standardization; 2007.Search in Google Scholar
11. Westgard, JO, Klee, GG. Quality management. In: Burtis, CA, Ashwood, ER, Bruns, DE, editors. Tietz textbook of clinical chemistry and molecular diagnostics, 4th ed. Oxford, UK: Elsevier Saunders; 2006:485–529 pp.Search in Google Scholar
12. Miller, WG, Jones, GR, Horowitz, GL, Weykamp, C. Proficiency testing/external quality assessment: current challenges and future directions. Clin Chem 2011;57:1670–80. https://doi.org/10.1373/clinchem.2011.168641.Search in Google Scholar PubMed
13. Stavelin, A, Meijer, P, Kitchen, D, Sandberg, S. External quality assessment of point-of-care international normalized ratio (INR) testing in Europe. Clin Chem Lab Med 2012;50:81–8. https://doi.org/10.1515/cclm.2011.719.Search in Google Scholar
14. Braga, F, Pasqualetti, S, Panteghini, M. The role of external quality assessment in the verification of in vitro medical diagnostics in the traceability era. Clin Biochem 2018;57:23–8. https://doi.org/10.1016/j.clinbiochem.2018.02.004.Search in Google Scholar PubMed
15. van den Besselaar, AM, Witteveen, E, van der Meer, FJ. Long-term stability of frozen pooled plasmas stored at −70 degrees C, −40 degrees C, and −20 degrees C for prothrombin time and International Normalized Ratio (INR) assessment. Thromb Res 2013;131:349–51. https://doi.org/10.1016/j.thromres.2013.01.020.Search in Google Scholar PubMed
16. CLSI. Collection, transport, and processing of blood specimens for testing plasma-based coagulation assays and molecular hemostasis assays, approved guideline, 5th ed. Wayne, Pennsylvania, USA: Clinical and Laboratory Standards Institute; 2008, CLSI document H21-A5.Search in Google Scholar
17. van den Besselaar, A, Cobbaert, CM. Assignment of international normalized ratio to frozen and freeze-dried pooled plasmas. Clin Chem Lab Med 2020;58:2089–97. https://doi.org/10.1515/cclm-2019-1321.Search in Google Scholar PubMed
18. ISO13528. Statistical methods for use in proficiency testing by interlaboratory comparison, 2nd ed. Geneva, Switzerland: International Organization for Standardization; 2015.Search in Google Scholar
19. ISO/IEC17043. Conformity assessment – general requirements for proficiency testing, 1st ed. Geneva, Switzerland: International Organization for Standardization; 2010.Search in Google Scholar
20. Bukve, T, Stavelin, A, Sandberg, S. Effect of participating in a quality improvement system over time for point-of-care C-reactive protein, glucose, and hemoglobin testing. Clin Chem 2016;62:1474–81. https://doi.org/10.1373/clinchem.2016.259093.Search in Google Scholar PubMed
21. Stavelin, A, Sandberg, S. Harmonization activities of Noklus – a quality improvement organization for point-of-care laboratory examinations. Clin Chem Lab Med 2019;57:106–14. https://doi.org/10.1515/cclm-2018-0061.Search in Google Scholar PubMed
22. Zurcher, M, Sulzer, I, Barizzi, G, Lammle, B, Alberio, L. Stability of coagulation assays performed in plasma from citrated whole blood transported at ambient temperature. Thromb Haemostasis 2008;99:416–26. https://doi.org/10.1160/th07-07-0448.Search in Google Scholar PubMed
23. VIM. International vocabulary of metrology – basic and general concepts and associated terms, 3th ed.; 2008, JCGM 200:2008 (E/F).Search in Google Scholar
24. ISO17593. Clinical laboratory testing and in vitro medical devices – requirements for in vitro monitoring systems for self-testing of oral anticoagulant therapy, 1st ed. Geneva, Switzerland: International Organization for Standardization; 2007.Search in Google Scholar
25. Horowitz, GL. Proficiency testing matters. Clin Chem 2013;59:335–7. https://doi.org/10.1373/clinchem.2012.197574.Search in Google Scholar PubMed
26. van den Besselaar, A, van Rijn CJJ, Abdoel, CF, Chantarangkul, V, Scalambrino, E, Kitchen, S, et al.. Paving the way for establishing a reference measurement system for standardization of plasma prothrombin time: harmonizing the manual tilt tube method. J Thromb Haemostasis 2020;18:1986–94. https://doi.org/10.1111/jth.14873.Search in Google Scholar PubMed PubMed Central
27. van den Besselaar, A, van Rijn CJJ, Hubbard, AR, Kitchen, S, Tripodi, A, Cobbaert, CM. Requirement of a reference measurement system for the tissue factor-induced coagulation time and the international normalized ratio. Clin Chem Lab Med 2019;57:e169–72. https://doi.org/10.1515/cclm-2018-1194.Search in Google Scholar PubMed
28. WHO. Expert committee on biological standardization. Geneva: World Health Organization; 2017:58–9 pp, Techical Report Series 1004, 67th Report.Search in Google Scholar
29. van den Besselaar, A, Chantarangkul, V, Angeloni, F, Binder, NB, Byrne, M, Dauer, R, et al.. International collaborative study for the calibration of proposed International Standards for thromboplastin, rabbit, plain, and for thromboplastin, recombinant, human, plain. J Thromb Haemostasis 2018;16:142–9. https://doi.org/10.1111/jth.13879.Search in Google Scholar PubMed
30. Ovrebust, LJ, Ruperti, M, Valebjorg, C. Urgent field safety notice. Norway: Roche Diagnostics; 2018. SBN-CPS-2018-004.Search in Google Scholar
Supplementary Material
This article contains supplementary material (https://doi.org/10.1515/cclm-2022-1080).
© 2022 Walter de Gruyter GmbH, Berlin/Boston
