Sheffield, United Kingdom
Sheffield, United Kingdom

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Kristoffersen A.-H.,University of Bergen | Thue G.,University of Bergen | Ajzner E.,Josa Andras Teaching Hospital | Claes N.,Hasselt University | And 15 more authors.
Thrombosis Research | Year: 2012

Introduction: Standardisation of treatment with vitamin K antagonists (VKAs) is still an issue after 60 years of use. The study aimed to explore aspects of VKA monitoring in primary and secondary care. Methods: Two case histories were distributed to physicians in 13 countries. Case history A focused on a patient with atrial fibrillation on stable anticoagulation (latest INR 2.3). Physicians were asked about frequency of INR measurement, when to change the VKA dose, and the patient's annual risk of ischemic stroke and bleeding. Case history B focused on a patient with an unexpected INR of 4.8, asking for the patient's 48-hour bleeding risk, the immediate dose reduction and time until a repeat INR. Results: Altogether, 3016 physicians responded (response rate 8 - 38%), of which 82% were from primary care and 18% from secondary care. Answers varied substantially within and between countries regardless of level of care and VKA used. Median number of weeks between INR measurements was 4 - 6 weeks. Median threshold INR for increasing or decreasing the VKA dose was 1.9 and 3.1, respectively. Risk of ischemic stroke and bleeding were overestimated 2 - 3 times. In case history B, the median dose reduction the two first days was 75% for GPs and 55% for specialists, irrespective of estimates of bleeding risk; with one week to a repeat INR. Conclusion: Variation in VKA monitoring is substantial implying clinical consequences. Guidelines seem either unknown or may be considered impracticable. Further efforts towards standardisation of VKA management are needed. © 2012 Elsevier Ltd.


Jennings I.,UK NEQAS Blood Coagulation | Walker I.D.,UK NEQAS Blood Coagulation | Kitchen S.,UK NEQAS Blood Coagulation | Kitchen D.,UK NEQAS Blood Coagulation | And 5 more authors.
International Journal of Laboratory Hematology | Year: 2012

Introduction: The quality of anticoagulation management is not readily or frequently assessed, particularly between different centres. This study sought to evaluate agreement in oral anticoagulant management decisions between participating centres in UK NEQAS programmes. Methods: Participants were asked to indicate whether they used computerized dosing support software (CDSS) and to complete a series of questions with respect to anticoagulant management provision. Four clinical scenarios were provided, together with past and current International Normalised Ratio (INR) results. Participants were asked to provide recommendations on the target INR they would assign to the patient, the dose of warfarin and a recall interval. Results: Seven hundred and fifty-nine centres returned results, of which 28% were enrolled in the hospital-based EQA programme, and 72% were participants in the point-of-care testing programme. Six hundred (79%) reported use of CDSS. In one straightforward scenario, there was 99% agreement in dose recommendation. However, for three more complex scenarios, differences were apparent in target INRs employed and both dose and recall recommendations. In some cases, differences related to the software system employed. Conclusion: The study emphasizes large variation in the approach to managing these scenarios and warrants further investigation, together with education including promoting national guidelines for the assignment of target ranges. © 2011 Blackwell Publishing Ltd.


Kitchen S.,UK NEQAS Blood Coagulation | Kitchen S.,Sheffield Haemophilia and Thrombosis Center | Jennings I.,UK NEQAS Blood Coagulation | Makris M.,UK NEQAS Blood Coagulation | And 4 more authors.
Haemophilia | Year: 2016

Introduction: Although the variability in factor VIII (FVIII):C measurement is well recognized, this has not been widely reported for post-FVIII infusion samples. Aim/Methods: Three samples from haemophilia A patients were distributed in a UK National External Quality Assessment Scheme survey, each after treatment with either ReFacto AF, Kogenate FS or Advate. Fifty-two UK haemophilia centres performed FVIII assays using one-stage (n = 46) and chromogenic (n = 10) assays. Centres calibrated assays with the local plasma standard and with ReFacto AF laboratory standard for the ReFacto AF sample. Results/Conclusions: Chromogenic assays gave significantly higher results than one-stage assays (P < 0.0001, 32% difference) in the post-Kogenate sample but not in the post-ReFacto AF (11% higher by chromogenic assay, ns) or post-Advate samples (3% lower by chromogenic, ns) when assays were calibrated with plasma standards. Twenty centres used all Instrumentation Laboratory (IL)-activated partial thromboplastin time reagents (Synthasil)/IL deficient plasma/reference plasma) in the one-stage assay and 15 used all Siemens reagents (Actin FS/Siemens deficient plasma/reference plasma); this made a significant difference to results post-ReFacto AF (41% higher by IL reagents, P < 0.0001) and Advate (39% higher by IL reagents, P < 0.0001), but not Kogenate (7% higher by IL, ns) when calibrated with plasma standards. Differences between results obtained with different one-stage assay reagents for monitoring Advate have implications for dosing patients. Furthermore, there was considerable inter-laboratory variation as indicated by CVs in the range 15–26% for chromogenic assay and 12–19% for one-stage assay results. This study suggests that external quality assessment schemes should offer participation in post-FVIII infusion schemes where haemophilic patients are monitored. © 2016 John Wiley & Sons Ltd


PubMed | UK NEQAS Blood Coagulation
Type: Journal Article | Journal: International journal of laboratory hematology | Year: 2011

The quality of anticoagulation management is not readily or frequently assessed, particularly between different centres. This study sought to evaluate agreement in oral anticoagulant management decisions between participating centres in UK NEQAS programmes.Participants were asked to indicate whether they used computerized dosing support software (CDSS) and to complete a series of questions with respect to anticoagulant management provision. Four clinical scenarios were provided, together with past and current International Normalised Ratio (INR) results. Participants were asked to provide recommendations on the target INR they would assign to the patient, the dose of warfarin and a recall interval.Seven hundred and fifty-nine centres returned results, of which 28% were enrolled in the hospital-based EQA programme, and 72% were participants in the point-of-care testing programme. Six hundred (79%) reported use of CDSS. In one straightforward scenario, there was 99% agreement in dose recommendation. However, for three more complex scenarios, differences were apparent in target INRs employed and both dose and recall recommendations. In some cases, differences related to the software system employed.The study emphasizes large variation in the approach to managing these scenarios and warrants further investigation, together with education including promoting national guidelines for the assignment of target ranges.


PubMed | UK NEQAS Blood Coagulation
Type: Journal Article | Journal: Haemophilia : the official journal of the World Federation of Hemophilia | Year: 2016

Although the variability in factor VIII (FVIII):C measurement is well recognized, this has not been widely reported for post-FVIII infusion samples.Three samples from haemophilia A patients were distributed in a UK National External Quality Assessment Scheme survey, each after treatment with either ReFacto AF, Kogenate FS or Advate. Fifty-two UK haemophilia centres performed FVIII assays using one-stage (n = 46) and chromogenic (n = 10) assays. Centres calibrated assays with the local plasma standard and with ReFacto AF laboratory standard for the ReFacto AF sample.Chromogenic assays gave significantly higher results than one-stage assays (P < 0.0001, 32% difference) in the post-Kogenate sample but not in the post-ReFacto AF (11% higher by chromogenic assay, ns) or post-Advate samples (3% lower by chromogenic, ns) when assays were calibrated with plasma standards. Twenty centres used all Instrumentation Laboratory (IL)-activated partial thromboplastin time reagents (Synthasil)/IL deficient plasma/reference plasma) in the one-stage assay and 15 used all Siemens reagents (Actin FS/Siemens deficient plasma/reference plasma); this made a significant difference to results post-ReFacto AF (41% higher by IL reagents, P < 0.0001) and Advate (39% higher by IL reagents, P < 0.0001), but not Kogenate (7% higher by IL, ns) when calibrated with plasma standards. Differences between results obtained with different one-stage assay reagents for monitoring Advate have implications for dosing patients. Furthermore, there was considerable inter-laboratory variation as indicated by CVs in the range 15-26% for chromogenic assay and 12-19% for one-stage assay results. This study suggests that external quality assessment schemes should offer participation in post-FVIII infusion schemes where haemophilic patients are monitored.

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