What are the indications for referral to a haematologist in patients diagnosed with essential thrombocythaemia?

Indications for referral to a haematologist in patients diagnosed with essential thrombocythaemia include:

• Persistent and unexplained thrombocytosis over 450 × 10⁹/L for more than 3 months, or platelet counts over 600 × 10⁹/L on at least two occasions 4–6 weeks apart.
• Platelet counts within 600–1000 × 10⁹/L accompanied by recent arterial or venous thrombosis (such as deep vein thrombosis, pulmonary embolism, cerebrovascular accident, transient ischaemic attack, myocardial infarction, unstable angina, or peripheral vascular disease), neurological symptoms, abnormal bleeding, age over 60 years, or other significantly abnormal full blood count indices.
• Platelet counts over 1000 × 10⁹/L warrant urgent referral.
• Any uncertainty regarding diagnosis or suspicion of a myeloproliferative disorder, especially if JAK2 mutation testing is negative but other features such as high platelets, enlarged spleen, family history of myeloproliferative disease, or previous thrombosis are present.

Referral to haematology is essential for further investigation, confirmation of diagnosis, and management of essential thrombocythaemia to reduce risks of thrombosis and other complications.

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