European Concerted Action on Anticoagulation. A multicentre calibration study of WHO international reference preparations for thromboplastin, rabbit (RBT/90) and human (rTF/95). Issue 6 (25th May 2005)

• Record Type: Journal Article
• Authors: Poller, L; Keown, M; Chauhan, N; van den Besselaar, A M H P; Tripodi, A; Shiach, C; Jespersen, J
• Is Part Of: Journal of clinical pathology. Volume 58:Issue 6(2005)
• Page Start: 667
• Page End: 669
• Publication Date: 2005-05-25
• Subjects: CV, coefficient of variation -- ECAA, European Concerted Action on Anticoagulation -- INR, international normalised ratio -- IRP, international reference preparation -- ISI, international sensitivity index -- PR, prothrombin ratio -- PT, prothrombin time -- WHO, World Health Organisation; international normalised ratio -- international sensitivity index -- multicentre calibration -- international reference preparation; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jcp.2004.019810
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : A 10 centre calibration was performed after six years to determine the international sensitivity index (ISI) of rTF/95 relative to RBT/90, and to assess any international normalised ratio (INR) bias compared with the original multicentre calibration. After exclusion of one outlying centre, the follow up calibration gave a mean ISI for rTF/95 of 0.99, which although a small difference, is significantly greater than the mean ISI of 0.94 obtained previously. The change in ISI for international reference preparation (IRP) rTF/95 relative to RBT/90 would lead to a slight bias in INR for human compared with rabbit thromboplastins. At a theoretical INR of 3.0, the INR bias is 6.0%, and this is below the accepted 10% level of clinical relevance. Ongoing stability monitoring of World Health Organisation thromboplastin IRP is advised.