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J Thromb Haemost. 2018 Jan;16(1):142-149. doi: 10.1111/jth.13879. Epub 2017 Dec 1.

International collaborative study for the calibration of proposed International Standards for thromboplastin, rabbit, plain, and for thromboplastin, recombinant, human, plain.

Author information

1
Department of Thrombosis and Hemostasis, and Coagulation Reference Laboratory, Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands.
2
Fondazione Luigi Villa, Milano, Italy.
3
Hemostasis Reference Laboratory, Hamilton, Canada.
4
Technoclone GmbH, Vienna, Austria.
5
National Coagulation Laboratory, St James's Hospital, Dublin, Ireland.
6
Haematology Laboratory, Pathology Department, Alfred Health, Melbourne, Australia.
7
Department of Laboratory Hematology and Hemostasis Center, Landspitali University Hospital and University of Iceland School of Medicine, Reykjavik, Iceland.
8
Department of Clinical Biochemistry, Hospital of South West Jutland and Unit for Health Promotion Research, Institute of Public Health, University of Southern Denmark, Esbjerg, Denmark.
9
Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, Sheffield, UK.
10
Department of Angiology and Blood Coagulation, University Hospital S. Orsola-Malpighi, Bologna, Italy.
11
Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
12
Department of Coagulation, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK.
13
Grupo Bioquímico, Laboratorio Central del Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.
14
Department of Hematology-Oncology, School of Medicine, Pontifical Catholic University of Chile, Santiago, Chile.
15
Clinical Cardiology, Department of Cardiac, Thoracic, and Vascular Sciences, University of Padova, Padova, Italy.
16
Haemophilia Laboratory (HSL), Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London, UK.
17
Department of Transfusion Medicine and Immunohaematology, St John's Medical College Hospital, Bangalore, India.
18
Hemostasis Laboratory, St István and St László Hospital, Budapest, Hungary.
19
Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
20
Roche Diagnostics GmbH Mannheim, Mannheim, Germany.
21
Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Department of Clinical Sciences and Community Health, Università degli Studi di Milano and IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy.

Abstract

Essentials Two candidate International Standards for thromboplastin (coded RBT/16 and rTF/16) are proposed. International Sensitivity Index (ISI) of proposed standards was assessed in a 20-centre study. The mean ISI for RBT/16 was 1.21 with a between-centre coefficient of variation of 4.6%. The mean ISI for rTF/16 was 1.11 with a between-centre coefficient of variation of 5.7%.

SUMMARY:

Background The availability of International Standards for thromboplastin is essential for the calibration of routine reagents and hence the calculation of the International Normalized Ratio (INR). Stocks of the current Fourth International Standards are running low. Candidate replacement materials have been prepared. This article describes the calibration of the proposed Fifth International Standards for thromboplastin, rabbit, plain (coded RBT/16) and for thromboplastin, recombinant, human, plain (coded rTF/16). Methods An international collaborative study was carried out for the assignment of International Sensitivity Indexes (ISIs) to the candidate materials, according to the World Health Organization (WHO) guidelines for thromboplastins and plasma used to control oral anticoagulant therapy with vitamin K antagonists. Results Results were obtained from 20 laboratories. In several cases, deviations from the ISI calibration model were observed, but the average INR deviation attributabled to the model was not greater than 10%. Only valid ISI assessments were used to calculate the mean ISI for each candidate. The mean ISI for RBT/16 was 1.21 (between-laboratory coefficient of variation [CV]: 4.6%), and the mean ISI for rTF/16 was 1.11 (between-laboratory CV: 5.7%). Conclusions The between-laboratory variation of the ISI for candidate material RBT/16 was similar to that of the Fourth International Standard (RBT/05), and the between-laboratory variation of the ISI for candidate material rTF/16 was slightly higher than that of the Fourth International Standard (rTF/09). The candidate materials have been accepted by WHO as the Fifth International Standards for thromboplastin, rabbit plain, and thromboplastin, recombinant, human, plain.

KEYWORDS:

International Normalized Ratio; anticoagulants; calibration; prothrombin time; thromboplastin

PMID:
29065247
DOI:
10.1111/jth.13879

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