Increased Haemoglobin


Elevated haemoglobin and haematocrit levels can reflect decreased plasma volume (due to dehydration, alcohol, smoking, diuretics) or increased red cell mass (polycythaemia).

Polycythaemia may be secondary (usually to chronic hypoxia from chronic lung disease, but occasionally to erythropoietin-secreting tumours, especially renal tumours, fibroids) or primary (polycythaemia vera).

Primary polycythaemia or polycythaemia vera (PV):

  • often has splenomegaly and increased white cell counts and platelets
  • is a myeloproliferative neoplasm and is mostly associated with a Janus Kinase 2 (JAK2) mutation
  • occurs in adults, between 50 and 70 years
  • is associated with an increased incidence of venous and arterial thromboses
  • may progress onto other disorders such as acute leukaemia or myelofibrosis


History and Examination

Consider history:

  • Thrombosis or vascular event
  • Respiratory or renal disease
  • Examine every patient for splenomegaly, as this is a key diagnostic criteria for polycythaemia vera (PV)

Red Flags

Evidence of thrombosis or vascular event and raised haematocrit greater than 0.52 (males) or greater than 0.48 (females) warrants acute medical admission


  • Renal function, Midstream urine, ferritin, O2 saturation (chronic hypoxia is the most common cause of secondary PV)
  • Neutrophila and thrombocytosis are often seen with primary PV


If raised haematocrit greater than 0.52 (males) or greater than 0.48 (females) and evidence of:

  • thrombosis, vascular event, or other haematological abnormalities, arrange an acute general medicine assessment
  • respiratory or another secondary cause, treat and manage
  • if associated neutrophilia and/or thrombocytosis refer to haematology
  • if raised haemoglobin level persists and no secondary cause found refer to haematology for further assessment

Urgent or written haematology advice is available

Referral Instructions

e-Referral Service Selection

  • Specialty: Haematology
  • Clinic Type: Not Otherwise Specified
  • Service: DRSS-Northern-Haematology- Devon CCG- 15N

Referral Forms

DRSS Referral Form

Supporting Information

This guideline has been signed off by the Northern Eastern Western Locality on behalf of NEW Devon CCG

Publication Date: July 2016


Home > Referral > Northern locality > Haematology > Increased Haemoglobin


  • First line
  • Second line
  • Specialist
  • Hospital