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

A M H P van den Besselaar, V Chantarangkul, F Angeloni, N B Binder, M Byrne, R Dauer, B R Gudmundsdottir, Jørgen Jespersen, S Kitchen, C Legnani, T L Lindahl, R A Manning, M Martinuzzo, O Panes, V Pengo, A Riddell, S Subramanian, A Szederjesi, C Tantanate, P HerbelA Tripodi

Research output: Contribution to journalJournal articleResearchpeer-review

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.

Original languageEnglish
JournalJournal of Thrombosis and Haemostasis
Volume16
Issue number1
Pages (from-to)142-149
ISSN1538-7933
DOIs
Publication statusPublished - 2018

Keywords

  • Journal Article
  • International Normalized Ratio
  • anticoagulants
  • prothrombin time
  • thromboplastin
  • calibration
  • Recombinant Proteins/standards
  • Predictive Value of Tests
  • Rabbits
  • Prothrombin Time/standards
  • Reproducibility of Results
  • Laboratory Proficiency Testing
  • Humans
  • Thromboplastin/standards
  • Calibration
  • Anticoagulants/therapeutic use
  • Blood Coagulation/drug effects
  • Drug Monitoring/standards
  • Reference Standards
  • Animals
  • International Normalized Ratio/standards
  • Observer Variation

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