Intended for healthcare professionals

Clinical Review

The diagnosis and management of erythrocytosis

BMJ 2013; 347 doi: (Published 18 November 2013) Cite this as: BMJ 2013;347:f6667
  1. Clodagh Keohane, research fellow in myeloproliferative neoplasms1,
  2. Mary Frances McMullin, professor of clinical haematology2,
  3. Claire Harrison, professor of haematology1
  1. 1Haematology Department, Guy’s and St Thomas’ NHS Foundation Trust, London SE1 9RT, UK
  2. 2Haematology Department, Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, UK
  1. Correspondence to: C Harrison Claire.Harrison{at}

Summary points

  • Erythrocytosis is a common reason for referral to haematology services and is usually secondary in origin

  • Referral thresholds for iron replete patients are packed cell volume persistently >0.52 in men and >0.48 in women

  • The cause can often be elucidated from a detailed medical and drug history

  • Common secondary causes include smoking, hypoxia, and diuretics

  • Intervention is not always indicated, and the decision to venesect is often made on a case by case basis after a risk-benefit assessment

  • True polycythaemia vera is rare. It carries an increased risk of thrombosis and progression to myelofibrosis or leukaemia and requires specialist management

Erythrocytosis is an increase in the number of red blood cells. In a recent study from the United States, the prevalence of primary erythrocytosis (known as polycythaemia vera) was 44-57 per 100 000.1 The prevalence of secondary erythrocytosis is considerably higher but is difficult to quantify owing to the diversity of causes and paucity of data. This review aims to provide an update on the diagnostic pathway for patients presenting with erythrocytosis, as well as up to date appraised data on the management of such patients.

Sources and selection criteria

We searched PubMed to identify peer reviewed original articles, meta-analyses, and reviews. We considered only those papers that were written in English, published from 1966 until the present day, which described studies that had adequate scientific validity. The authors’ own collections and older references generated from initial papers were also examined. Randomised trials and series of patients and single case reports were considered if appropriate.

What is the definition of erythrocytosis?

Erythrocytosis is suspected when haemoglobin is above 185 g/L or the packed cell volume is greater than 0.52 in a man or 165 g/L and 0.48, respectively, in a woman. The packed cell volume is a measure of the volume percentage of red blood cells in whole blood. In …

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