RT Journal Article
SR Electronic
T1 INR derivation with the PT/INR Line simplified using a spreadsheet from the world wide web
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 930
OP 932
DO 10.1136/jclinpath-2011-200068
VO 64
IS 10
A1 Poller, Leon
A1 Ibrahim, Saied
A1 Pattison, Albert
A1 Jespersen, Jørgen
A1 ,
YR 2011
UL http://jcp.bmj.com/content/64/10/930.abstract
AB 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.