Abdul Mannan: BDUC – 4 Letters That Make Many Haematologists Uncomfortable
Abdul Mannan, Consultant Haematologist at Betsi Cadwaladr University Health Board, shared on LinkedIn:
”BDUC. Four letters that make many haematologists uncomfortable.
Bleeding Disorder of Unknown Cause. The patient bleeds. Your tests are normal.
Now what?
I’ve developed a 4-step systematic approach to navigate this clinical challenge:
Step 1: The Gatekeeper
Apply ISTH-BAT Score (≥4 men, ≥6 women, ≥3 children)
If normal, stop. No hemostatic workup needed.
Check for hypermobility syndromes and medication culprits (NSAIDs, SSRIs, garlic, ginkgo)
Step 2: Rule Out Common Disorders
CBC, blood film, routine coagulation, VWF screen (≥0.50 IU/mL required)
First-line platelet function (LTA with agonists)
Remember: Inflammation masks mild VWD and Haemophilia A
Step 3: Hunt for Rare Disorders
If Step 2 is normal but bleeding history is convincing, test FXIII (delayed wound healing!) and Factors II, V, VII, IX, XI, X
Consider dense granule deficiency with ATP:ADP ratio or electron microscopy
Step 4: Confirm BDUC
High BAT score + completely normal Steps 2 and 3 equals BDUC confirmed
Test fibrinolytic defects only if delayed bleeding or umbilical stump issues (ASH 2025)
TEG, ROTEM, NGS? Not standard of care. Low yield.
Two pitfalls I see repeatedly: Overlooking iron deficiency (worsens platelet function)
Testing FVIII/VWF during pregnancy or inflammation (falsely normal)
The visual flowchart is in the comments below.
What’s your approach when bleeding history is strong but labs are normal?”

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