Coagulometer international sensitivity index (ISI) derivation, a rapid method using the prothrombin time/international normalized ratio (PT/INR) Line: a multicenter study

Poller, L.; Ibrahim, Said A.; Jespersen, Jørgen; Pattison, A.

doi:10.1111/j.1538-7836.2012.04751.x

Cited by 10 publications

(10 citation statements)

References 14 publications

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“… The PT/INR line, based on a simple procedure using a selected set of only five EAA lyophilised test plasmas to derive a laboratory's local INR , has been shown to provide closely similar INRs to the more demanding and time‐ consuming FDA‐approved simplified ISI calibration. It has proved dependable over a large range of prothrombin time methods and has recently been advocated by the ESC Task Force on Anticoagulants’ , which stated that it achieves reliable INR without the need for local ISI calibrations.…”

Section: Commentsmentioning

confidence: 99%

Warfarin or dabigatran for treatment of atrial fibrillation

Poller

Jespersen

Ibrahim

2014

Journal of Thrombosis and Haemostasis

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Summary. Background: New antithrombotic drugs for prevention and treatment of thromboembolic disorders in AF that are less demanding on local staff and facilities than warfarin should be welcomed if proved successful. Objectives: The comparative value and possible dangers of substituting the new drug dabigatran as a replacement remain to be established. Its safety and effectiveness must be reviewed and assessed by further study. Methods: Clinical results of the European Action on Anticoagulation (EAA) computer-assisted dosage study and the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial have been compared. Results: Clinical events were lower in patients on warfarin in the EAA study compared to patients on both warfarin and dabigatran in the RE-LY study. Conclusion: Evaluations should recognize optimum requirements for safe and effective administration of both types of drug. In the warfarin arm improvements in effectiveness and safety recently introduced (i.e. the PT/INR line and variance growth analysis) should be included as they have been shown to be successful in improved prediction of bleeding and further thromboembolism. The incidence of bleeding with dabigatran, for which there is no antidote, will require evaluation.

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Section: Commentsmentioning

confidence: 99%

Warfarin or dabigatran for treatment of atrial fibrillation

Poller

Jespersen

Ibrahim

2014

Journal of Thrombosis and Haemostasis

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“…5 From the slope and y-intercept of the calibration line, the local ISI and MNPT were derived as follows: ISI = 1/slope, and MNPT = 10 y-intercept . 21 We also determined "ISI localB " by using local calibrator B, which has a set of six pooled lyophilized plasmas with certified INR values according to the method above. 5,7,21 …”

Section: Determination Of Two Local Isis (Isi Locala Isi Localb )mentioning

confidence: 99%

“…21 We also determined "ISI localB " by using local calibrator B, which has a set of six pooled lyophilized plasmas with certified INR values according to the method above. 5,7,21 …”

Section: Determination Of Two Local Isis (Isi Locala Isi Localb )mentioning

confidence: 99%

Significance of Local International Sensitivity Index Systems for Monitoring Warfarin and Liver function

Lee

Kim

Lee

et al. 2014

American Journal of Clinical Pathology

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“…In a recent multicentre study, Poller et al. [7] have validated the PT/INR line for coagulometer‐specific ISI derivation. Six participants in that study used Innovin and STA‐R as the local reagent/instrument combination.…”

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confidence: 99%

“…In the Poller et al. [7] study, coagulometer‐specific ISI values and MNPT after local calibration with the ECAA calibrator set and the PT/INR line were 0.99 and 9.8 s and 1.06 and 10.6 s, respectively. The ECAA colleagues state that coagulometer‐specific ISI values ‘can be derived for the range of locally used thromboplastins and automated PT systems listed in the published EAA reports and without the need for the demanding WHO ISI calibration’ [2].…”

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Artificially depleted plasmas are not necessarily commutable with native patient plasmas for International Sensitivity Index calibration and International Normalized Ratio derivation: a rebuttal

Fattorini

Crippa

D’Angelo

2012

Journal of Thrombosis and Haemostasis

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To cite this article: Fattorini A, Crippa L, DÕAngelo A. Artificially depleted plasmas are not necessarily commutable with native patient plasmas for International Sensitivity Index calibration and International Normalized Ratio derivation: rebuttal. J Thromb Haemost 2012; 10: 1715-6. We read with interest the letter by van den Besselar [1] about ISI calibrant plasmas and the ensuing exchange of correspondence with Poller et al. [2,3]. We agree with the ECAA colleagues that with the FDA-approved ECAA set of artificially depleted plasmas and the PT/INR line, inter-laboratory INR deviations are significantly reduced with all types of reagents, but we also suspect that, unless fresh native plasmas from patients on warfarin are used for calibration, this may not translate in better laboratory monitoring of patients on warfarin. van den Besselar [1] and Tripodi et al. [4] have reported discrepancies in INR between fresh and lyophilized samples with two rabbit thromboplastins and different coag-ulometers, but, given the advanced explanation of a different clotting factor composition of artificially depleted and native plasmas [3], we are afraid that such a discrepancy may also occur with reagents other than rabbit thromboplastins. With a STAR coagulometer and assuming Neoplastin Plus (Stago, Asniere sur Seine, France) as reference thromboplastin (certified coagulometer-specific ISI = 1.31) we have calculated on fresh plasma samples from stable patients on warfarin a coagulometer-specific ISI value of 0.77 (with Tomenson correction = 1.09) for Innovin (Siemens GmbH, Marburg, Germany) [5], which was confirmed in an independent series of 100 patients on warfarin [6]. In a recent multicentre study, Poller et al. [7] have validated the PT/INR line for coagulometer-specific ISI derivation. Six participants in that study used Innovin and STAR as the local reagent/instrument combination. The average stated values of these laboratories for ISI and MNPT before local calibration with either the ECAA set or the PT/INR line were 0.94 and 9.3 s, respectively. Given that no STAR specific ISI value for Innovin is provided by the manufacturer, we suspect that the stated ISI values were derived by local ISI calibration with the PT-Multi Calibrator set (Siemens), because using this set for the above-mentioned series of 100 patients on warfarin we have found a very similar STAR specific ISI value for Innovin of 0.96 (95% confidence interval, 0.95-0.97) with a derived MNPT of 10.2 s. According to the manufacturer, this set of six calibrator plasmas is obtained by pooling stabilized human plasma samples, some also containing a portion of animal plasma or of pretreated human plasma, followed by lyophilization. In the Poller et al. [7] study, coagulometer-specific ISI values and MNPT after local calibration with the ECAA calibrator set and the PT/INR line were 0.99 and 9.8 s and 1.06 and 10.6 s, respectively. The ECAA colleagues state that coagulo-meter-specific ISI values Ôcan be derived for the range of locally used thromboplastins and aut...

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Coagulometer international sensitivity index (ISI) derivation, a rapid method using the prothrombin time/international normalized ratio (PT/INR) Line: a multicenter study

Cited by 10 publications

References 14 publications

Warfarin or dabigatran for treatment of atrial fibrillation

Warfarin or dabigatran for treatment of atrial fibrillation

Significance of Local International Sensitivity Index Systems for Monitoring Warfarin and Liver function

Artificially depleted plasmas are not necessarily commutable with native patient plasmas for International Sensitivity Index calibration and International Normalized Ratio derivation: a rebuttal

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