Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program

Salazar, Eric; Long, Thomas; Smock, Kristi J.; Wool, Geoffrey D.; Rollins‐Raval, Marian A.; Chen, Dong; Harris, Neil; Chan, Clarence W; Olson, John D.; Pham, Huy P.; Ritter, Jacob; Unold, David; VanSandt, Amanda M.; Goodwin, Andrew

doi:10.1055/s-0042-1749591

Cited by 6 publications

(28 citation statements)

References 16 publications

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“…14 15 Of additional interest, CAP identifies that the manufacturer provided lowest reportable value were 19% (HemosIL VWF activity assay [VWF:Ab], Instrumentation Laboratories/Werfen, Lexington, MA) and 20% (BC Von Willebrand Reagent, Siemens Healthineers, Marburg, Germany [VWF:RCo]). 16 Similarly high assay “limits of VWF detection” were evident or reported by RCPAQAP participants for several VWF assays and samples in recent exercises. 14 15…”

Section: Learning From Eqamentioning

confidence: 70%

“…14,15 Of additional interest, CAP identifies that the manufacturer provided lowest reportable value were 19% (HemosIL VWF activity assay [VWF:Ab], Instrumentation Laboratories/Werfen, Lexington, MA) and 20% (BC Von Willebrand Reagent, Siemens Healthineers, Marburg, Germany [VWF:RCo]). 16 Similarly high assay "limits of VWF detection" were evident or reported by RCPAQAP participants for several VWF assays and samples in recent exercises. 14,15 Optimal Cut-off Values for Type 1 versus 2 VWD Discrimination Several EQA programs have provided data that helps identify "optimal" cut-off values for type 1 versus 2 (A, B) VWD discrimination based on assays and samples assessed within their program.…”

Section: Vwf Assay Variation and Limits Of Vwf Detectionmentioning

confidence: 73%

“…This follows to some extent expectations based on tests available or regulatory cleared/approved in different locations. Thus, CAP users predominantly utilize VWF:Ab, 16 whereas very few Australasian laboratory participants of RCPQAP do so. 14 The trend to replace VWF:RCo with VWF:GPIbR or VWF:GPIbM is evident in both RCPAQAP 14 and NEQAS 17 data, but limited in CAP 16 Table 5 VWD Guidelines -some similarities and some differences a Laffan et al, 2014 [52] James et al, 2021 [50] Various [4,7,25,28,37,44,45,47] Initial test panel no.…”

Section: Learning From Eqamentioning

confidence: 99%

“…The other programs did not specifically report on diagnostic errors, but may instead report on participant interpretation for separate individual assays (e.g., normal vs. abnormal). 16,17,18,19 Tests and Test Panels Used across Different Geographies…”

Section: Errors In Vwd Diagnosismentioning

confidence: 99%

“…Interestingly, NASCOLA data 18 tended to confirm 0.7 as a preferred cut-off with assays dominant in North America, whereas UK NEQAS data seemed to favor 0.6 as the better cut-off 17. CAP could not provide data on cut-off values due to sample issues 16. The discrepancies in EQA findings relate both to sample bias (i.e., reflective of the actual samples tested by participants in these surveys), as well as test differences (i.e., reflective of the tests in use by participants in these surveys).…”

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confidence: 98%

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Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives

Favaloro

Pasalic

2022

Semin Thromb Hemost

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Abstractvon 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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Section: Learning From Eqamentioning

confidence: 70%

Section: Vwf Assay Variation and Limits Of Vwf Detectionmentioning

confidence: 73%

Section: Learning From Eqamentioning

confidence: 99%

Section: Errors In Vwd Diagnosismentioning

confidence: 99%

mentioning

confidence: 98%

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Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives

Favaloro

Pasalic

2022

Semin Thromb Hemost

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Evaluating Performance of Contemporary and Historical von Willebrand Factor (VWF) Assays in the Laboratory Identification of von Willebrand Disease (VWD): The Australasian Experience

Favaloro

Dean

Arunachalam

2022

Semin Thromb Hemost

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Abstractvon 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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Laboratory Diagnostics for Thrombosis and Hemostasis Testing—Part I

Smock

Gosselin

2022

Semin Thromb Hemost

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Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program

Cited by 6 publications

References 16 publications

Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives

Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives

Evaluating Performance of Contemporary and Historical von Willebrand Factor (VWF) Assays in the Laboratory Identification of von Willebrand Disease (VWD): The Australasian Experience

Laboratory Diagnostics for Thrombosis and Hemostasis Testing—Part I

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