Register Login

Local ISI (or INR) Calibration

It seems strange North American coagulation laboratories have not adopted local ISI or INR calibration despite articles such as Poller L, Keown M, Ibrahim S, et al. Comparison of local International Sensitivity Index calibration and ‘direct INR’ methods in correction of locally reported International Normalized Ratios: an international study. J Thromb Haemost 2007;5:1002-9 and Adcock DM, Johnston M. Evaluation of frozen plasma calibrants for enhanced standardization of the International Normalized Ratio (INR): A multi-center study. Thromb Haemost 2002; 87:74-9 that demonstrate improved local INR accuracy and lot-to-lot stability. Further…
…two international standards exist; van den Besselaar AM, Barrowcliffe TW, Houbouyan-Reveillard LL, et al. Guidelines on preparation, certification, and use of certified plasmas for ISI calibration and INR determination, J Thromb Haemost 2004;2:1946-53; and Clinical and Laboratory Standards Institute (CLSI). Procedures for Validation of INR and Local Calibration of PT/INR Systems; Approved Guideline. CLSI document H54-A (ISBN 1-56238-580-1). The van den Besselaar guidelines were developed by the Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society for Thrombosis and Hemostasis (ISTH).

I recall Pacific Hemostasis offered certified INR validation plasmas in the USA in 1995, but does any distributor currently offer a plasma set, or at least is anyone in the process of applying to the FDA? Geo.

Comments (1)
Jan 6, 2010 2:39pm

You may already be aware that Instrumentation Laboratory Co.
You may already be aware that Instrumentation Laboratory Co. (IL) recently received 510(k) clearance from FDA to market HemosIL INR Validate, HemosIL ISI Calibrate, and ISIweb Software to allow IL users to verify INR accuracy and to perform local ISI calibrations. The approval letter from FDA may be found at .

Leave a Reply