Effect of coagulation factors on discrepancies in International Normalized Ratio results between instruments

Sølvik, Una Ørvim; Røraas, Thomas; Petersen, Per Hyltoft; Stavelin, Anne; Monsen, Grete; Sandberg, Sverre

doi:10.1515/cclm-2011-0820

Cited by 10 publications

(4 citation statements)

References 16 publications

(31 reference statements)

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“…In a cohort of non-APS patients, Solvik et al demonstrated that different plasma levels of coagulation factors (i.e. fibrinogen, factors II, VII, IX and X) in blood samples from anticoagulated patients play an important role in explaining discrepancies between the different INR test methods [26]. Additionally, the tissue factor content, the phospholipid composition and differences in ISI calibration may contribute to differences observed in the INR measurements using different thromboplastins [5,9,14].…”

Section: Inr Differences Between Different Pt Assaysmentioning

confidence: 99%

Monitoring anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome

et al. 2015

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Because of the possible interference of antiphospholipid antibodies (APL) with the phospholipid component of thromboplastin reagents, concerns have been raised about the validity of international normalized ratio (INR) testing to monitor anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome (APS). To investigate the reliability of the INR, we determined the INR using various prothrombin time (PT) assays and compared the results with those of a chromogenic factor X (CFX) assay. The study cohort consisted of 40 APS patients and 100 APL-negative patients who were on anticoagulant therapy for reasons other than APS. The agreement (i.e. the percentage of patients with a difference ≤0.5 INR units) between the PT-derived INR and CFX-derived INR equivalents was only moderate in both patient groups. The best agreement with CFX-derived INR equivalents was observed for the Thromborel S reagent in APS patients (69.1 %) and for Neoplastin Plus in APL-negative patients (72.0 %). Regarding the results for the point-of-care system CoaguChek XS, an agreement between the INR and the CFX-derived INR equivalent was less frequently observed in the APS patients (55.6 vs. 67.8 %; p = 0.050). When considering all 3058 pairs of INR tests within the international sensitivity index (ISI)-calibrated range of 1.5 to 4.5 s, we did not observe a higher variability of INR values in either the APS patient group or the subgroup of APS patients positive for lupus coagulants compared with the APL-negative controls. In conclusion, monitoring vitamin K antagonists (VKA) therapy with laboratory INR measurements seems to be suitable for the majority of APS patients.

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Section: Inr Differences Between Different Pt Assaysmentioning

confidence: 99%

Monitoring anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome

et al. 2015

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“…This is in accord with previous findings, showing that different coagulation factor levels in plasma may play a role in justifying discrepancies between POC-INR instrumentation. 19 The plasma source used by UK NEQAS was not disclosed in their publication, 8 but personal communications from NEQAS identify the source as primarily patient derived. This likely helps (at least in part) explain the relatively lower CVs from UK NEQAS compared with RCPAQAP.…”

Section: Discussionmentioning

confidence: 99%

International Normalized Ratio Monitoring of Vitamin K Antagonist Therapy: Comparative Performance of Point-of-Care and Laboratory-Derived Testing

Bonar

Mohammed

Favaloro

2015

Semin Thromb Hemost

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The monitoring of warfarin therapy using the international normalized ratio (INR) has now moved outside the laboratory's control by use of point-of-care (POC) devices. Although this provides patients with the convenience of immediate results and clinical assessment, POC-INRs are often performed by nonlaboratory staff with little experience in quality control. The Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) Haematology has devised a POC-INR external quality assessment (EQA) program that is suitable for both laboratory and nonlaboratory operators (e.g., nurses) to perform INR testing with good accuracy and precision. A comparison of the performance of the POC versus the laboratory-derived INR testing over the past 8 years has shown that the variation in test results (expressed as coefficient of variation; CV) for laboratory INRs increases with more prolonged INR values, whereas CVs for the POC-INR testing were generally lower, with a reduced dependency on INR values. In our program, the CoaguChek XS (Roche, Basel, Switzerland) showed the best performance among the POC devices. A comparative assessment with other EQA providers showed agreement and disparity with our data in terms of comparative CVs obtained between the laboratory and POC-INRs. The growth of the RCPAQAP POC-INR program from 29 to 360 in the past 12 years highlights the importance of providing suitable EQA for POC-INR staff who are unfamiliar with laboratory practice. This helps maintaining consistent results, which have important implications for the therapeutic management of patients on vitamin K antagonist therapy.

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“…8 Several factors, including antiphospholipid syndrome, heparinization, and use of oral anticoagulants, may cause over or underestimation of the results. [18][19][20][21] In the liver transplant population specifically, endogenous heparinoids released in liver failure, residual exogenous heparin from the donor harvesting procedures, and the effects of recombinant tissue plasminogen activator (administered into the hepatic graft as part of some donation after cardiac death protocols) may be contributory to inaccuracies in the measures. 1,22 The HEMOCHRON Jr. Signature utilizes light-emitting diode optical detectors to determine clot formation below a predetermined threshold.…”

Section: Discussionmentioning

confidence: 99%

Reliability of a point-of-care device for international normalized ratio testing during the three surgical phases of orthotopic liver transplantation: a retrospective observational study

Mace

Lightfoot

Cordero-Rochet

et al. 2015

Can J Anesth/J Can Anesth

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Purpose To investigate the reliability of a point-of-care device, the HEMOCHRON Ò Jr. Signature, for measuring the international normalized ratio (INR) during the three surgical phases of liver transplantation. Methods A retrospective review was performed on patients undergoing liver transplantation during July to December 2013. Thirty-one patients who had simultaneous laboratory and point-of-care INR readings from each phase of liver transplant surgery (paleohepatic, anhepatic, and neohepatic) were eligible for inclusion. Bland-Altman analysis, Spearman's rank correlation, and four quadrant plots were used to compare INR results from the point-ofcare device (pocINR) with those from the laboratory (labINR). Results Based on the Bland-Altman analysis, mean biases (95% prediction interval) were 0.10 (0.03 to 0.17), 0.19 (0.12 to 0.27), and 0.21 (0.01 to 0.43) for the paleohepatic, anhepatic, and neohepatic phases, respectively. The pocINR device showed a systematic underestimation of the labINR. The Spearman's rank correlation coefficients (95% confidence interval [CI]) were: Q = 0.90 (95% CI 0.80 to 0.95); Q = 0.92 (95% CI 0.71 to 0.93); and Q = 0.71 (95% CI 0.46 to 0.85), respectively. Direction-of-change analysis between the paleohepatic to anhepatic and the anhepatic to neohepatic phases showed strong concordance of 84% and, also considering the small bias between the measurements, supports the use of the pocINR device in the clinical management of liver transplant surgery. Conclusion Point-of-care INR was accurate prior to hepatic reperfusion, but reliability decreased in the neohepatic phase. RésuméObjectif É tudier la fiabilité d'un dispositif au chevet, l'HEMOCHRON Ò Jr. Signature, pour la mesure du rapport international normalisé (RIN) pendant les trois phases chirurgicales d'une transplantation hépatique. Méthodes : Une analyse rétrospective a été menée sur des patients ayant subi une transplantation hépatique entre juillet et décembre 2013. Trente et un patients ayant des

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Effect of coagulation factors on discrepancies in International Normalized Ratio results between instruments

Cited by 10 publications

References 16 publications

Monitoring anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome

Monitoring anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome

International Normalized Ratio Monitoring of Vitamin K Antagonist Therapy: Comparative Performance of Point-of-Care and Laboratory-Derived Testing

Reliability of a point-of-care device for international normalized ratio testing during the three surgical phases of orthotopic liver transplantation: a retrospective observational study

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