Normal Counts, High Risk: Abdul Mannan Breaks Down JAK2 + Splanchnic Vein Thrombosis
Abdul Mannan, Consultant Haematologist at Betsi Cadwaladr University Health Board, posted on LinkedIn:
”You find JAK2V617F in a patient with splanchnic vein thrombosis. Counts are normal. The marrow doesn’t show MPN. Now what?
Here’s the thing: JAK2 positivity in SVT means clonal, persistent risk. It doesn’t disappear just because the blood count looks normal.
Here’s what the evidence tells us:
• JAK2+ SVT behaves as a chronic prothrombotic state, even without overt MPN on counts or marrow
• Budd-Chiari syndrome should get indefinite anticoagulation from the start (target INR 2-3 with LMWH or VKA )
• Portal or mesenteric vein thrombosis with JAK2 positivity usually needs extended or indefinite anticoagulation, tailored to bleeding risk
• Ruxolitinib (Jakavi) is NOT standard for thrombosis prevention alone – it may help if an overt MPN later declares itself, but it doesn’t replace anticoagulation
• Cytoreduction isn’t indicated when counts are truly normal
Here’s what matters for follow-up: some patients do progress to overt MPN over time. One cohort had 30% declare MPN at a median of 41 months. So you’re looking at periodic CBCs, iron studies if polycythemia concerns you, and keeping step with hepatology for varices and bleeding risk.
The lesson for clinic: don’t withhold anticoagulation waiting for “diagnostic” marrow features, and don’t reach for ruxolitinib to avoid anticoagulation. Both are misses.
What’s your approach when JAK2 shows up in unusual thrombosis?”
Keep up with Hemostasis Today.
-
Mar 13, 2026, 22:57Robert Hamilton: The Reality of Stroke Care and Why 81.6% Should be a Wake-Up call
-
Mar 13, 2026, 21:29Timothy Glidewell: Genetic Signals of Platelet and Clotting Pathways in Cryptogenic Stroke
-
Mar 13, 2026, 21:19New Canadian Insights on Switching to Longer-Acting Therapy for Hemophilia A – WFH
-
Mar 13, 2026, 21:01Leonardo Roever: Brain Age as a Biomarker of Neuroplasticity and Motor Recovery After Stroke
-
Mar 13, 2026, 20:50William Tembo: Understanding Stroke Through Landmark Clinical Trials
-
Mar 13, 2026, 20:35Jessica Garcia: New Evidence on Thrombin Generation Patterns in Children with Hemophilia A
-
Mar 13, 2026, 20:11Christoph B. Olivier: New Research from Marius Wessinger on Predicting Therapy Success After Pulmonary Embolism
-
Mar 13, 2026, 19:53Wolfgang Miesbach Announces the New English Edition of “Gene Therapy Concepts in the Treatment of Haemophilia”
-
Mar 13, 2026, 17:21Emmanuel J Favaloro: Acquired Hemostasis Disorders Featured in New Issue of Seminars in Thrombosis and Hemostasis