Polycythemia (erythrocytosis)

Who to refer:

• Patients with a persistently raised venous haematocrit (Hct) for at least 3 months (and on three separate tests) should be investigated.
• Please refer males with Hct > 0.52 and females with Hct > 0.48.
• If Hct doesn’t meet above values but low MCV with disproportionately high Hb/Hct, check serum ferritin.  If ferritin low, this may represent an iron deficient polycythaemia vera, hence referral appropriate.

Urgent investigation of polycythaemia is required If there is a history of arterial thrombosis, or evidence of recent acute occlusive events.

Who not to refer:

• Patients who do not fulfil the above criteria.
• If severe hypoxia/lung disease, initial referral to respiratory physicians more appropriate.

How to refer:

SCI Gateway to the Department of Haematology BGH

Primary care investigations

• Serial FBCs at least 1 month apart.
• Serum ferritin.
• Pulse oximetry
• General evaluation for any possible contributory cause e.g. CXR, SpO₂ if hypoxic pulmonary disease suspected.