ASSIGNMENT AND VALIDATION OF INR CONTROL AND CALIBRATOR SETS FOR LOCAL CALIBRATION OF INR
Abstract number: P-S-120
Hammelburger1 J., Bottenus1 R., Triscott1 M.
1Research and Development, Instrumentation Laboratory, Orangeburg, NY, United States
How-to-cite Hammelburger J, Bottenus R, Triscott M. ASSIGNMENT AND VALIDATION OF INR CONTROL AND CALIBRATOR SETS FOR LOCAL CALIBRATION OF INR. J Thromb Haemost 2007; 5 Supplement 2: P-S-120
Introduction: The use of INR controls for verification of laboratory INR and if necessary, the determination of a local international sensitivity index (ISI) was recommended by recent guidelines (ISTH/SSC and CLSI H54-A). HemosIL INR Validate and HemosIL ISI Calibrate certified plasmas, traceable to WHO Reference Laboratories, were evaluated with (IL) PT reagents and instruments.
Methods: Calibrate control plasmas (1 Normal and 3 Abnormal, INR from patients on OAT (range of 0.9-4.5)) and samples from Warfarin Anticoagulated patients (OAT), with assigned INR reference values traceable to the WHO lab certification, were tested for PT (sec) with 5 PT reagents on 4 different instruments. Calibration curves were generated using Direct INR with reagent-specific INR reference values and Local ISI using certified PT (sec). Validation control plasmas (3 Abnormal, INR 1.5-4.5 from patients on OAT), Calibrate control plasmas, and coumadin samples, were assigned INR reference values from the Direct INR calibration curves using curve specific ISI and MNPT. The coumadin samples were also analyzed for INRs using the manufacturer's instrument specific ISI and laboratory MNPT.
Results: The ISI values were comparable using the reagent-specific Direct INR or Local ISI assignment and within 10% of the manufacturer's instrument/reagent-specific ISI. A Bland-Altman analysis of paired samples indicated comparable INR recoveries among instruments and between INR from WHO certification, Direct INR and current INR assignment using label ISI and laboratory MNPT (<=0.1). The INR of the Validate controls using label ISI and laboratory MNPT fell within 15% of the assigned reference INR for each certified plasma.
Conclusions: INR values of the HemosIL Validate and Calibrate products are reagent-specific and can be used to verify INRs and generate Direct INR calibrations for accurate local ISI and MNPT on IL reagent/instrument systems. An IL Web-based program facilitated calculation of local PT/INR verifications and ISI assignment.
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Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number
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