Abdul Mannan: Advancing VWF Activity Testing Beyond VWF:RCo in Clinical Laboratories
Abdul Mannan, Consultant Hematologist at Betsi Cadwaladr University Health Board, shared a post on LinkedIn:
“Your VWF activity assay might be giving you the wrong answer.
And that wrong answer changes everything downstream.
VWF:RCo has been the workhorse of VWD testing for decades.
But here’s what the data actually shows:
- VWF:RCo imprecision sits around 9%. GPIb-based assays? Around 3.2%.
- Ristocetin-sensitive polymorphisms can falsely lower the activity:Ag ratio. That’s not biology. That’s assay noise.
- In diverse populations, this creates a predictable disadvantage. The same patient, different ethnicity, different result. That’s an equity problem.
Why does this matter so much?
The VWF activity result sits at the centre of the subtype algorithm. I
f that number drifts, everything drifts with it:
- Type 1 patients get pushed into a Type 2 work-up
- Unnecessary multimers, RIPA, genetics referrals follow
- DDAVP decisions and perioperative plans change
- Borderline cases get missed entirely
VWF:GPIbM offers a way out.
No ristocetin dependence.
No polymorphism distortion.
92% Type 2 sensitivity. 85.1% Type 1 specificity. Same 0.70 activity:Ag ratio threshold. Same diagnostic logic.
The message is simple: modernise the assay, preserve the pathway.
Both BSH 2024 and ASH/ISTH 2021 guidelines point the same direction.
But this isn’t just a reagent swap.
It’s a quality programme.
- Validation
- Reporting language
- Clinical education
- Post-go-live review
All need to land together.
I built an interactive guide to walk laboratories through this transition step by step.
- Assay comparison
- Decision algorithms
- Implementation framework
- Rhe evidence behind each choice
All in one place.
Has your lab made this switch yet?
What held you back, or what pushed you forward?”
Other posts featuring Abdul Mannan on Hemostasis Today.
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Nov 4, 2026, 18:57Connecting Haemophilia Centres, Certifying Treaters, and Improving National Data in Romania – EHC
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Nov 4, 2026, 18:45Smitirupa Mishra: A Practical Guide to Coagulation Pathway Assessment and Laboratory Interpretation
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Nov 4, 2026, 15:59Alessandra Bosch: A Successful Patient Day for the Bleeding Disorders Community in Zürich
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Nov 4, 2026, 15:47Wolfgang Miesbach: Targeting Hepatic Endothelial Cells for Lentiviral Gene Therapy in Haemophilia A
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Nov 4, 2026, 15:20Augustina Isioma Ikusemoro: Before You Transfuse, Think PBM
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Nov 4, 2026, 14:23Advancing Hemophilia Care Through Global Research – WFH
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Nov 4, 2026, 14:12Jean-Jacques Kiladjian: From JAK Inhibitor-Associated Skin Cancers to Laboratory Discovery
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Nov 4, 2026, 13:59Rita Li: ASH 2026 Abstract Achievement Award for Gut Microbiome Research
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Nov 4, 2026, 13:38Omid Seidizadeh: Improving Access to von Willebrand Disease Diagnosis and Treatment Across Europe