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Platton S, Baker P, Bowyer A, Keenan C, Lawrence C, Lester W, Riddell A, Sutherland M. Guideline for laboratory diagnosis and monitoring of von Willebrand disease: A joint guideline from the United Kingdom Haemophilia Centre Doctors' Organisation and the British Society for Haematology. Br J Haematol 2024; 204:1714-1731. [PMID: 38532595 DOI: 10.1111/bjh.19385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 03/28/2024]
Affiliation(s)
- Sean Platton
- Royal London Hospital Haemophilia Centre, London, UK
| | - Peter Baker
- Oxford Haemophilia and Thrombosis Centre, Nuffield Orthopaedic Hospital, Oxford, UK
| | - Annette Bowyer
- Department of Coagulation, Royal Hallamshire Hospital, Sheffield, UK
| | - Catriona Keenan
- Department of Haematology & the National Coagulation Centre, St. James's Hospital, Dublin, Ireland
| | | | - Will Lester
- Haemophilia Unit, University Hospitals, Birmingham, UK
| | - Anne Riddell
- Katharine Dormandy Haemophilia Centre, Royal Free Hospital, London, UK
| | - Megan Sutherland
- North West Genomic Laboratory Hub, Manchester University NHS Foundation Trust, Manchester, UK
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2
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Favaloro EJ. The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History. Semin Thromb Hemost 2024; 50:43-80. [PMID: 36807283 DOI: 10.1055/s-0043-1763259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The von Willebrand factor (VWF) collagen binding (VWF:CB) assay was first reported for use in von Willebrand diagnostics in 1986, by Brown and Bosak. Since then, the VWF:CB has continued to be used to help diagnose von Willebrand disease (VWD) (correctly) and also to help assign the correct subtype, as well as to assist in the monitoring of VWD therapy, especially desmopressin (DDAVP). However, it is important to recognize that the specific value of any VWF:CB is predicated on the use of an optimized VWF:CB, and that not all VWF:CB assays are so optimized. There are some good commercial assays available, but there are also some "not-so-good" commercial assays available, and these may continue to give the VWF:CB "a bad reputation." In addition to VWD diagnosis and management, the VWF:CB found purpose in a variety of other applications, from assessing ADAMTS13 activity, to investigation into acquired von Willebrand syndrome (especially as associated with use of mechanical circulatory support or cardiac assist devices), to assessment of VWF activity in disease states in where an excess of high-molecular-weight VWF may accumulate, and lead to increased (micro)thrombosis risk (e.g., coronavirus disease 2019, thrombotic thrombocytopenic purpura). The VWF:CB turns 37 in 2023. This review is a celebration of the utility of the VWF:CB over this nearly 40-year history.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
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3
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Favaloro EJ, Pasalic L. Laboratory diagnosis of von Willebrand disease in the age of the new guidelines: considerations based on geography and resources. Res Pract Thromb Haemost 2023; 7:102143. [PMID: 37601016 PMCID: PMC10439443 DOI: 10.1016/j.rpth.2023.102143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/05/2023] [Accepted: 06/21/2023] [Indexed: 08/22/2023] Open
Abstract
von Willebrand disease (VWD) is considered the most common bleeding disorder and arises from deficiency and/or defect in the adhesive plasma protein von Willebrand factor (VWF). Diagnosis of VWD requires clinical assessment and is facilitated by laboratory testing. Several guidelines for VWD diagnosis exist, with the latest American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia 2021 guidelines presenting 11 recommendations, some of which have drawn controversy. In the current narrative review, we provide additional context around difficulties in laboratory diagnosis/exclusion/typing of VWD, with a focus on developing countries/resource-poor settings. In particular, there are many variations in assay methodology, and some methods express high assay variability and poor low-level VWF sensitivity that compromises their utility. Although we favor an initial 4-test assay panel, comprising factor (F) VIII coagulant activity, VWF antigen, VWF glycoprotein Ib binding (VWF:GPIbR or VWF:GPIbM favored over VWF Ristocetin cofactor) and VWF collagen binding, we also provide strategies for laboratories only able to incorporate an initial 3-test assay panel, as favored by the latest guidelines, to improve diagnostic accuracy.
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Affiliation(s)
- Emmanuel J. Favaloro
- Haematology, Sydney Centres for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
| | - Leonardo Pasalic
- Haematology, Sydney Centres for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
- Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
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4
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Ziemba YC, Abdulrehman J, Hollestelle MJ, Meijer P, Plumhoff E, Hsu P, Selby R. Diagnostic Testing for von Willebrand Disease: Trends and Insights from North American Laboratories over the Last Decade. Semin Thromb Hemost 2022; 48:700-710. [PMID: 36122573 DOI: 10.1055/s-0042-1754332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Accurate diagnosis of von Willebrand disease (VWD) depends on the quality, precision, and variability of the laboratory assays. The North American Specialized Coagulation Laboratory Association (NASCOLA) is a provider of external quality assessment (EQA) for approximately 60 specialized coagulation laboratories in North America. In this report, NASCOLA EQA data from 2010 to 2021 are reviewed for trends in methodology and precision among various assays. In particular, recent ASH ISTH NHF WFH (American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Hemophilia Federation) guidelines for diagnosis of VWD are reviewed in light of EQA data. In contrast to other geographic regions, laboratories in North America predominantly use three-assay screening panels (antigen, platelet-binding activity, and factor VIII [FVIII] activity) rather than four-assay panels (antigen, platelet-binding activity, FVIII activity, and collagen-binding activity). They also use latex immunoassays rather than chemiluminescence immunoassays, and the classic ristocetin cofactor (VWF:RCo) assay and monoclonal antibody (VWF:Ab) assay to assess VWF platelet-binding activity over newer recommended assays (VWF:GPIbM and VWF:GPIbR). Factors that may be influencing these North American practice patterns include lack of Food and Drug Administration approval of the VWF:GPIbM, VWF:GPIbR, collagen binding assays, and chemiluminescence methodologies, and the influence of the 2008 National Heart, Lung, and Blood Institute guidelines on laboratory practice. Lastly, systems-based solutions are urgently needed to improve the overall accuracy of laboratory testing for VWD by minimizing preanalytical variables and adopting assay standardization.
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Affiliation(s)
- Yonah C Ziemba
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York
| | | | | | - Piet Meijer
- ECAT Foundation, Voorschoten, the Netherlands
| | - Elizabeth Plumhoff
- North American Specialized Coagulation Laboratory Association, Rochester, Minnesota
| | - Peihong Hsu
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York
| | - Rita Selby
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,North American Specialized Coagulation Laboratory Association, Rochester, Minnesota.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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5
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Salazar E, Long TA, Smock KJ, Wool GD, Rollins-Raval M, Chen D, Harris NS, Chan CW, Olson JD, Pham HP, Ritter J, Unold D, VanSandt AM, Goodwin Iv AJ. Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program. Semin Thromb Hemost 2022. [PMID: 36063852 DOI: 10.1055/s-0042-1757132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Von Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.
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Affiliation(s)
- Eric Salazar
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Thomas A Long
- Department of Biostatistics, College of American Pathologists, Northfield, Illinois
| | - Kristi Johnson Smock
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, Utah
| | - Geoffrey D Wool
- Department of Pathology, University of Chicago, Chicago, Illinois
| | | | - Dong Chen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | | | - Clarence W Chan
- Department of Pathology, University of Chicago Medical Center, Chicago, Illinois
| | - John D Olson
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Huy P Pham
- Seattle Apheresis Collection Center, National Marrow Donor Program (NMDP)Seattle, Washington
| | - Jacob Ritter
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - David Unold
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California
| | - Amanda Matzke VanSandt
- Department of Pathology and Laboratory Medicine, Oregon Health & Science University, Portland, Oregon
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6
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Jennings I, Reilly-Stitt C, Lowe A, Kitchen S, Walker I. External Quality Assessment Data for Investigation of von Willebrand Disease: Focus on Relative Utility of Contemporary Functional von Willebrand Factor Assays. The United Kingdom National External Quality Assessment Scheme (UK NEQAS) Experience. Semin Thromb Hemost 2022; 48:732-738. [PMID: 36055268 DOI: 10.1055/s-0042-1753512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Von Willebrand disease (VWD) is one of the most common hereditary bleeding disorders. Effective management of patients and their families depends on accurate diagnosis and subtype classification, and quality assurance including participation in proficiency testing programs is essential to ensure the accuracy of the panel of assays required to achieve this diagnosis. We report here findings from recent external quality assessment (EQA) exercises, as well as from a questionnaire about diagnostic practices employed by centers in the United Kingdom National Quality Assessment Scheme (UK NEQAS) performing von Willebrand factor (VWF) assays. Plasma samples from donors with VWD, "normal" donors, the International Society for Thrombosis and Haemostasis Scientific Subcommittee (ISTH SSC) plasma standard, and whole blood samples were sent to participants in the UK NEQAS BC program for VWF investigation. Calibration of lot#5 of the ISTH SSC plasma standard was shown to give improved comparability between the recovered value from an EQA exercise and the assigned potency for VWF activity assays. Diagnostic accuracy and precision amongst UK NEQAS participants was good, with an average 99% of centers reporting the correct interpretation for normal, type 1 and type 2 VWD samples, 100% diagnostic accuracy for centers performing FVIII binding assays, and good agreement amongst centers performing multimeric analysis. Genetic analysis of the VWF gene by specialist centers demonstrated errors in the genotyping process in one center, but also demonstrated failings in the interpretation of results in other centers. Despite evidence of good laboratory accuracy and precision in their assays, a questionnaire identified marked variation in diagnostic criteria employed, underlining the importance of guidelines to support the diagnosis of VWD.
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Affiliation(s)
- Ian Jennings
- Department of Blood Coagulation, UK NEQAS, Sheffield, United Kingdom
| | | | - Anna Lowe
- Department of Blood Coagulation, UK NEQAS, Sheffield, United Kingdom
| | - Steve Kitchen
- Department of Blood Coagulation, UK NEQAS, Sheffield, United Kingdom
| | - Isobel Walker
- Department of Blood Coagulation, UK NEQAS, Sheffield, United Kingdom
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7
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Favaloro EJ, Pasalic L. Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives. Semin Thromb Hemost 2022; 48:750-766. [PMID: 36055264 DOI: 10.1055/s-0042-1754331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
von Willebrand disease (VWD) is reportedly the most common inherited bleeding disorder, and can also arise as an acquired (von Willebrand) syndrome (AVWS). The hemostasis laboratory plays a key role in the diagnosis or exclusion of VWD/AVWS, which may otherwise be suspected due to the patient's clinical (bleeding) history. VWD/AVWS arise from deficiency and/or defects in the adhesive plasma protein, von Willebrand factor (VWF). VWF undertakes various roles within hemostasis, but principally acts within primary hemostasis to anchor platelets to sites of vascular damage, thereby facilitating thrombus formation to arrest bleeding. The diagnosis or exclusion of VWD/AVWS requires laboratory testing for both VWF level and activity, with the latter potentially comprising several of a potential plethora of different assays. Complete diagnosis of VWD also requires the differentiation of VWD type, with six types comprising the current classification (i.e., qualitative [types 2A, 2B, 2M, 2N VWD] vs. quantitative [types 1 and 3 VWD] deficiency/defects). Although appropriate diagnosis and type classification hold important therapeutic consequences, these remain problematic and sometimes elusive for some laboratories to achieve. This report reviews the laboratory aided diagnosis or exclusion of VWD from a geographic perspective, and focuses on the disparities of approaches and methods in different regions of the world. This is primarily done from the perspective of data available from published reports related to external quality assessment (or proficiency testing) from different geographic localities. Moreover, differences in approaches between laboratories may arise due to differential adherence of particular guidelines, as well as regulatory aspects and predominance of local manufacturers and suppliers.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, North South Wales, Australia
| | - Leonardo Pasalic
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Westmead Clinical School, University of Sydney, Westmead, North South Wales, Australia
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8
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Salazar E, Long TA, Smock KJ, Wool GD, Rollins-Raval M, Chen D, Harris NS, Chan CW, Olson JD, Pham HP, Ritter J, Unold D, VanSandt AM, Goodwin Iv AJ. Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program. Semin Thromb Hemost 2022; 48:690-699. [PMID: 36055272 DOI: 10.1055/s-0042-1749591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Von Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.
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Affiliation(s)
- Eric Salazar
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Thomas A Long
- Department of Biostatistics, College of American Pathologists, Northfield, Illinois
| | - Kristi Johnson Smock
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, Utah
| | - Geoffrey D Wool
- Department of Pathology, University of Chicago, Chicago, Illinois
| | | | - Dong Chen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | | | - Clarence W Chan
- Department of Pathology, University of Chicago Medical Center, Chicago, Illinois
| | - John D Olson
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Huy P Pham
- Seattle Apheresis Collection Center, National Marrow Donor Program (NMDP)Seattle, Washington
| | - Jacob Ritter
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - David Unold
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California
| | - Amanda Matzke VanSandt
- Department of Pathology and Laboratory Medicine, Oregon Health & Science University, Portland, Oregon
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Salazar E, Long TA, Smock KJ, Wool GD, Rollins-Raval M, Chen D, Harris NS, Chan CW, Olson JD, Pham HP, Ritter J, Unold D, VanSandt AM, Goodwin IV AJ. Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program. Semin Thromb Hemost 2022; 48:690-699. [DOI: 10.1055/s-0042-1758161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractVon Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.
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Affiliation(s)
- Eric Salazar
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Thomas A. Long
- Department of Biostatistics, College of American Pathologists, Northfield, Illinois
| | - Kristi Johnson Smock
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, Utah
| | - Geoffrey D. Wool
- Department of Pathology, University of Chicago, Chicago, Illinois
| | | | - Dong Chen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | | | - Clarence W. Chan
- Department of Pathology, University of Chicago Medical Center, Chicago, Illinois
| | - John D. Olson
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - Huy P. Pham
- Seattle Apheresis Collection Center, National Marrow Donor Program (NMDP)Seattle, Washington
| | - Jacob Ritter
- Department of Pathology and Laboratory Medicine, UT Health San Antonio, San Antonio, Texas
| | - David Unold
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California
| | - Amanda Matzke VanSandt
- Department of Pathology and Laboratory Medicine, Oregon Health & Science University, Portland, Oregon
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10
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Favaloro EJ, Dean E, Arunachalam S. Evaluating Performance of Contemporary and Historical von Willebrand Factor (VWF) Assays in the Laboratory Identification of von Willebrand Disease (VWD): The Australasian Experience. Semin Thromb Hemost 2022; 48:711-731. [PMID: 35803263 DOI: 10.1055/s-0042-1753528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
von Willebrand disease (VWD) is a common bleeding disorder that arises from deficiency and/or defects of von Willebrand factor (VWF). Appropriate diagnosis of VWD, including differential identification of qualitative (types 2A, 2B, 2M, 2N VWD) versus quantitative (types 1 and 3 VWD) defects remains problematic but has important management implications, given differential therapy. Complete assessment for VWD in a patient with a bleeding history requires comprehensive test panels, including VWF activity and antigen. We describe the Australasian experience, using data from the Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program (QAP) related to VWF testing in their VWD test module. The RCPAQAP has been providing samples for VWF testing since 1998, representing 25 years of proficiency testing related to VWD diagnosis. A total of 109 samples have been dispatched to participants over these years, with current assessment involving dispatches of two samples (=4 samples) per year. Samples have represented all types of VWD, as well as normal or other samples, including acquired von Willebrand syndrome and plasma VWF concentrates as used in VWD therapy. Different VWF assays and activity/antigen ratios show different utility in VWD and type identification. In the past 9 years of data capture, a total of 166 errors were identified from a total of 1,839 interpretations, representing a base error rate of 9.0%. Identification errors were highest for type 2 VWD samples (15.3%), intermediate for type 1 VWD samples (7.5%), and lowest for normal samples (2.4%). Errors can be linked to assay limitations, including assay variability and low-level VWF detection limits, as well as laboratory issues (including test result misinterpretation, which accounts for approximately 40% of all errors for type 2 VWD). For test-associated errors, VWF:RCo and VWF:GPIbM were associated with the highest variability and error rate, which was up to 10x higher than that using VWF:CB. As a test group, chemiluminescence-based procedures were associated with lowest inter-laboratory variability, best low-level VWF detection (down to <1 U/dL), and least errors overall. These findings inform on reasons behind high rates of errors associated with VWD diagnosis, with some assays and methodologies performing substantially better than others.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia.,Sydney Centers for Thrombosis and Haemostasis, Westmead, New South Wales Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Elysse Dean
- RCPAQAP Haematology, St Leonards, New South Wales, Australia
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11
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Favaloro EJ. Comparing the quality of testing for von Willebrand disease in different geographic localities. Haemophilia 2022; 28:193-196. [PMID: 35099101 PMCID: PMC9305405 DOI: 10.1111/hae.14499] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/02/2022] [Accepted: 01/19/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, New South Wales, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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