When should I consider referring a patient with Polycythaemia Vera to a haematologist?

Consider referring a patient with polycythaemia vera to a haematologist urgently if:

• Polycythaemia vera is suspected based on clinical and laboratory findings.
• The patient is experiencing symptoms of hyperviscosity (such as headache, dizziness, visual disturbances, or thrombosis).
• The patient tests negative for the JAK2 V617F mutation but has other features suggestive of a myeloproliferative disease, including high platelet or white blood cell counts, enlarged spleen, family history of myeloproliferative disease, previous thrombosis, or altered erythropoietin levels.
• There is uncertainty regarding the diagnosis and specialist advice is needed.
• Secondary erythrocytosis is suspected with elevated erythropoietin levels without chronic hypoxic disorder, to exclude erythropoietin-secreting malignancy or other rare causes.

Referral is also appropriate if the patient requires management of complications or treatment such as venesection, cytoreductive therapy, or aspirin, especially in those at high risk of thrombosis (age over 60 or history of thrombosis).

Specialist input is important for confirming diagnosis, managing treatment, and monitoring disease progression or complications.

Summary: Refer urgently to haematology if polycythaemia vera is suspected or confirmed, if symptoms of hyperviscosity occur, if JAK2 mutation testing is negative but clinical suspicion remains, or if elevated erythropoietin levels suggest other causes. Also refer for treatment initiation and ongoing management in secondary care ¹,².