The prothrombin time/international normalized ratio (PT/INR) Line: derivation of local INR with commercial thromboplastins and coagulometers - two independent studies

L. Poller*, S. Ibrahim, M. Keown, A. Pattison, J. Jespersen, S. Marun, W. Muntean, Gerold Aspoeck, Alex S. Gallus, E. Bailleul, William Wijns, T. Michel, Kristin Jochmans, B. Chatelain, Carlo L. M. Marcelis, A.S. Nijs de, M. Johnston, K. Kynde, M. Syrjala, E.-R. SavolainenK. Ivaska, A. Rajamaki, R. Vanharanta, I. Juhan, M.-F. Aillaud, M.-C. Guillin, M.-G. Huisse, P. Sie, T. Lecompte, Y. Schmitt, J. Harenberg, W. Plesch, S. Aronis, George Theodossiades, B. Tsoukanas, D. Markala, M. Ditsa, M. Cahill, M. Madden, B. White, B.T. Nolan, H. Fitzgerald, D. McCarthy, B. Collins, S. Rooney, E. Naparstek, G. Palareti, F. Marongiu, N. Erba, Sophie Testa, G. Mariani, R. Poti, P. M. Mannucci, A. Tripodi, R. Bader, Vittorio Pengo, Paolo Gresele, Marco D'inca, W. Ageno, Alberto Tosetto, H. E. S. J. Hensgens, R. N. Idema, D. H. Oosterhout, A. B. Mulder, K. Hamulyak, H. van der Dussen, J. Musial, T. Gago, A. Palmeiro, Manuel Campos, D. A. Marques-Dias, A. Cunha Monteiro, M. Angela Cunha, W. N. de Gaia, P. Peternel, M. Stegnar, J. Fontcuberta, M. Borrell, J. C. Reverter, P. Domenech Santasusana, M. Fernanda Lopez-Fernandez, José Luis Castro-Montero, C. Ribera Casado, Vicente Vicente, B. Edlund, N. Egberg, B. Laemmle, L. Alberio, P. de Moerloose, G. Reber, S. J. Machin, I. Mackie, A. Lawrie, J. Luckit, D. Shanks, G. Dolan, T. Flaherty, C. A. Ludlam, I. D. Walker, D. E. Lawson, M. Triscott, R. A. Marlar, J. A. Heit, H. Watzke, B. Weisser, J. Osmond, I. Cornet, A.-M. Munster, B. Leed, C. Chillou, M. Defard, M. H. Horellou, H. Halkin, R. Loebstein, I. Kirgner, F. Dentali, V. Trapani Lombardo, Gianluca Sottilotta, P. Consiglio, S. De Michele, M. Moia, Monica Carpenedo, C. Manotti, M. Ilaria Tassoni, B. Cosmi, C. Brusi, C. Legnani, C. Pegoraro, C. Andriani, M. Grazia Cirigliano, E. Ribaldi, R. Abbate, D. Poli, C. Perricone, M. Schiavuli, C. Casiera, M. R. Lupone, Emanuela Rossi, S. Crivelli, A. Birolini, F. Parente, A. M. Miglietta, M. Campobasso, W. Sydor, B. Krevel, T. M. A. Fernandez, Andres M. Lozano, C. Shiach, C. Bowyer, F. Charles

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


The WHO scheme for prothrombin time (PT) standardization has been limited in application, because of its difficulties in implementation, particularly the need for mandatory manual PT testing and for local provision of thromboplastin international reference preparations (IRP).The value of a new simpler procedure to derive international normalized ratio (INR), the PT/INR Line, based on only five European Concerted Action on Anticoagulation (ECAA) calibrant plasmas certified by experienced centres has been assessed in two independent exercises using a range of commercial thromboplastins and coagulometers. INRs were compared with manual certified values with thromboplastin IRP from expert centres and in the second study also with INRs from local ISI calibrations.In the first study with the PT/INR Line, 8.7% deviation from certified INRs was reduced to 1.1% with human reagents, and from 7.0% to 2.6% with rabbit reagents. In the second study, deviation was reduced from 11.2% to 0.4% with human reagents by both local ISI calibration and the PT/INR Line. With rabbit reagents, 10.4% deviation was reduced to 1.1% with both procedures; 4.9% deviation was reduced to 0.5% with bovine/combined reagents with local ISI calibrations and to 2.9% with the PT/INR Line. Mean INR dispersion was reduced with all thromboplastins and automated systems using the PT/INR Line.The procedure using the PT/INR Line provides reliable INR derivation without the need for WHO ISI calibration across the range of locally used commercial thromboplastins and automated PT systems included in two independent international studies.? 2010 International Society on Thrombosis and Haemostasis.
Original languageEnglish
Pages (from-to)140-148
JournalJournal of Thrombosis and Haemostasis
Issue number1
Publication statusPublished - Jan 2011


  • coagulometers
  • ECAA plasmas
  • INR correction
  • prothrombin time
  • PT
  • INR Line
  • thromboplastins

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