Thrombocytopenia: ITP, TTP and HIT
A low platelet count: excluding pseudothrombocytopenia, thresholds for bleeding and procedures (AABB/ICTMG 2025), ITP diagnosis and treatment (ANZ 2022, McMaster 2026 critical bleeding), TTP with PLASMIC and plasma exchange (ISTH 2025 update), HIT with the 4Ts, drug-induced and pregnancy causes.
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Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Thrombocytopenia is a platelet count under 150 x 10^9/L. Spontaneous serious bleeding is uncommon above about 10 to 20 x 10^9/L when platelets work normally.
- First confirm it: platelet clumping in EDTA gives false low counts.
- Then sort by mechanism: less production, more destruction or consumption, sequestration, or dilution.
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Sources
- Consensus guidelines for the management of adult immune thrombocytopenia in Australia and New ZealandAU/NZChoi PY et al., Med J Aust 2022;216:43-52, 2022
- Updated international consensus report on the investigation and management of primary immune thrombocytopeniaProvan D et al., Blood Adv 2019;3:3780-817, 2019
- American Society of Hematology 2019 guidelines for immune thrombocytopeniaNeunert C et al., Blood Adv 2019;3:3829-66, 2019
- Guideline on the emergency management of critical bleeding in patients with immune thrombocytopeniaChowdhury SR et al., Blood Adv 2026;10:5558-75, 2026
- 2025 focused update of the 2020 ISTH guidelines for management of thrombotic thrombocytopenic purpuraZheng XL et al., J Thromb Haemost 2025;23:3711-32, 2025
- Caplacizumab treatment for acquired thrombotic thrombocytopenic purpura (HERCULES)Scully M et al., N Engl J Med 2019;380:335-46, 2019
- Derivation and external validation of the PLASMIC score for rapid assessment of adults with thrombotic microangiopathiesBendapudi PK et al., Lancet Haematol 2017;4:e157-64, 2017
- American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopeniaCuker A et al., Blood Adv 2018;2:3360-92, 2018
- Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settingsLo GK et al., J Thromb Haemost 2006;4:759-65, 2006
- Platelet transfusion: 2025 AABB and ICTMG international clinical practice guidelinesMetcalf RA et al., JAMA 2025;334:606-17, 2025
- Schedule of Pharmaceutical Benefits, November 2026 (romiplostim, avatrombopag, eltrombopag)AU/NZAustralian Government Department of Health, Disability and Ageing, November 2026
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy