INR derivation with the PT/INR Line simplified using a spreadsheet from the world wide web. Issue 10 (22nd April 2011)

• Record Type: Journal Article
• Authors: Poller, Leon; Ibrahim, Saied; Pattison, Albert; Jespersen, Jørgen
• Is Part Of: Journal of clinical pathology. Volume 64:Issue 10(2011)
• Page Start: 930
• Page End: 932
• Publication Date: 2011-04-22
• Subjects: INR -- prothrombin time -- PT/INR Line -- ECAA plasmas -- polycythaemia -- erythrocyte -- haematology -- myeloproliferative disease -- anticoagulants -- computer assisted -- quality assurance -- safety -- colorectal cancer -- gall bladder -- oncogenes -- p53/attribute -- pancreas -- leukaemia -- polycythaemia; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jclinpath-2011-200068
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : Background: The prothrombin time/international normalised ratio (PT/INR) Line method to derive INR, based on only five European Concerted Action on Anticoagulation (ECAA) certified plasmas, is shown to be reliable in previous ECAA studies. A simpler method not requiring linear regression calculation would be an advantage. Method: After determining the local PT/INR Line, local INRs have been obtained using a readily available spreadsheet on the internet which laboratories can use without performing any additional calculations. Results: Examples of INR derivation have been obtained from results at 16 centres using a range of local coagulometers with human thromboplastin international reference preparations (IRPs). The procedure does not require manual PT testing, local international sensitivity index calibration, availability of thromboplastin IRPs or local mean normal prothrombin time. Conclusions: From the PT/INR Line, INR values for local PT results are easily obtained using an Excel spreadsheet from our website (http://www.anticoagulants.co.uk/ ) which does not require the complex linear regression analysis to derive INR.