Standards and monitoring treatment

Barrowcliffe, T W; Hubbard, A. R.; Kitchen, S.

doi:10.1111/j.1365-2516.2012.02831.x

Cited by 25 publications

(34 citation statements)

References 32 publications

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“…Potency labelling of FVIII and FIX concentrates uses either one‐stage or chromogenic assays referenced against the current World Health Organization (WHO) concentrate standard . The FVIII and FIX subcommittee of the Scientific and Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis (ISTH) recommends that if either the one‐stage or chromogenic method for FVIII activity provides valid potency estimates relative to the WHO IS for concentrates, this assay can be used for potency labelling .…”

Section: Use Of One‐stage and Chromogenic Assays In Potency Assignmenmentioning

confidence: 99%

Clinical utility and impact of the use of the chromogenic vs one‐stage factor activity assays in haemophilia A and B

Marlar

Strandberg

Shima

et al. 2019

European J of Haematology

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Treatment of haemophilia A/B patients comprises factor VIII (FVIII) or factor IX (FIX) concentrate replacement therapy, respectively. FVIII and FIX activity levels can be measured in clinical laboratories using one‐stage activated partial thromboplastin time (aPTT)‐based clotting or two‐stage chromogenic factor activity assays. We discuss strengths and limitations of these assays, providing examples of clinical scenarios to highlight some of the challenges associated with their current use for diagnostic and monitoring purposes. Substantial inter‐laboratory variability has been reported for one‐stage assays when measuring the activity of factor replacement products due to the wide range of currently available aPTT reagents, calibration standards, factor‐deficient plasmas, assay conditions and instruments. Chromogenic activity assays may avoid some limitations associated with one‐stage assays, but their regulatory status, perceived higher cost, and lack of laboratory expertise may influence their use. Haemophilia management guidelines recommend the differential application of one or both assays for initial diagnosis and disease severity characterisation, post‐infusion monitoring and replacement factor potency labelling. Efficient communication between clinical and laboratory staff is crucial to ensure application of the most appropriate assay to each clinical situation, correct interpretation of assay results and, ultimately, accurate diagnosis and optimal and safe treatment of haemophilia A or B patients.

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Section: Use Of One‐stage and Chromogenic Assays In Potency Assignmenmentioning

confidence: 99%

Clinical utility and impact of the use of the chromogenic vs one‐stage factor activity assays in haemophilia A and B

Marlar

Strandberg

Shima

et al. 2019

European J of Haematology

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show abstract

“…The test plasma result, expressed in seconds, is compared with a standard curve, generated from serial dilutions of a standard sample with known FVIII or FIX activity, which should be referenced against the current World Health Organisation (WHO) international standard (IS), also referred to as the primary standard, for the relevant plasma factor (ie FVIII or FIX). Most calibration materials that are manufactured for laboratory use are secondary standards determined relative to the WHO standards …”

Section: Principle and Methodology Of One‐stage And Chromogenic Fviiimentioning

confidence: 99%

“…For both OSAs and CSAs, testing against the WHO IS for FIX concentrates is required for potency labelling of new FIX products. However, the potency of the WHO FIX IS itself is often determined primarily by using results from OSAs . In addition, CSAs are currently not validated for potency labelling of new FIX products, and therefore, it is recommended that the relevance of FIX potencies determined using this method is assessed for each individual FIX product …”

Section: Comparison Of One‐stage and Chromogenic Fviii And Fix Activimentioning

confidence: 99%

Advantages, disadvantages and optimization of one‐stage and chromogenic factor activity assays in haemophilia A and B

Adcock

Strandberg

Shima

et al. 2018

Int J Lab Hematology

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Haemophilia A and B diagnosis and disease severity classification are determined on the basis of results from factor VIII (FVIII) and factor FIX (FIX) activity assays, respectively. These assays are also used for potency labelling, postinfusion monitoring of factor replacement products and testing for FVIII/FIX inhibitors. This review focuses on activated partial thromboplastin time (APTT)-based one-stage assays (OSAs) and two-stage chromogenic substrate assays (CSAs). Currently, there is considerable inter-laboratory variability in the results obtained using OSAs, which can be intensified in a reagent-specific manner by the presence of the new modified recombinant factor replacement products that are entering the market. Furthermore, the use of CSAs, which tend to show less variability, especially with the new modified products, is recommended in a number of clinical scenarios. Clinical laboratories may, therefore, need to establish CSAs for routine use. In this review, we aim to improve understanding and help establish best practices by describing the methodology behind OSAs and CSAs and highlighting assay advantages and limitations. We argue that there can be value in offering both assay methodologies in clinical laboratories that contribute to the care of patients with haemophilia A or B. Educating both laboratory scientists and clinicians about the strengths and weaknesses of each type of assay will help to establish the necessary dialogue that is key to ensuring not only that the appropriate assays are used in the right clinical situations, but also that the results are interpreted correctly.

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“…These standards define the International Unit (IU) and are available in limited quantities for calibration of local, commercial, national, and supranational standards; these in turn are used to assay therapeutic concentrates and plasma samples from patients and hence all such measurements can be recorded in IU [34]. These standards define the International Unit (IU) and are available in limited quantities for calibration of local, commercial, national, and supranational standards; these in turn are used to assay therapeutic concentrates and plasma samples from patients and hence all such measurements can be recorded in IU [34].…”

Section: Potency and Labeling Issuesmentioning

confidence: 99%

Products Used to Treat Hemophilia: Plasma‐derived Coagulation Factor Concentrates

Giangrande

2014

Textbook of Hemophilia

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Standards and monitoring treatment

Cited by 25 publications

References 32 publications

Clinical utility and impact of the use of the chromogenic vs one‐stage factor activity assays in haemophilia A and B

Clinical utility and impact of the use of the chromogenic vs one‐stage factor activity assays in haemophilia A and B

Advantages, disadvantages and optimization of one‐stage and chromogenic factor activity assays in haemophilia A and B

Products Used to Treat Hemophilia: Plasma‐derived Coagulation Factor Concentrates

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