Last updated: Friday, 28, January, 2011
CausesAppropriate Tests

Review clinical findings, including history of smoking and diuretic therapy.

Follow up FBC, blood film, red cell mass.

Relative polycythaemia

The apparent erythrocytosis is due to reduced plasma volume, eg Dehydration, Diuretic therapy.

Stress polycythaemia (spurious polycythaemia)

Gaisböck syndrome, associated with smoking and alcohol use.

May require measurement of blood volume to exclude absolute erythrocytosis.

Absolute polycythaemia 

Blood volume may be required to document absolute increase in red cell mass. Erythropoietin may be useful: increased levels in secondary erythrocytosis, low to undetectable levels in polycythaemia rubra vera.

Chronic hypoxaemia

Blood gases/haemoximetry. See also Cyanosis.

  • Heavy smoking
See Smoking
  • Cyanotic congenital heart disease
  • Respitory disease

Renal disorders

  • Polycystic kidney disease
See Cystic renal disease
  • Renal artery stenosis 

See under Hypertension.

  • Renal cell carcinoma 

See under Renal cell mass.

  • Hydronephrosis

See under Urinary tract obstruction.


  • Uterine myoma
  • Cerebellar haemangioblastoma

Primary haematological disorder

High affinity haemoglobin 

Haemoglobin oxygen affinity, Haemoglobin electrophoresis; haemoglobin M.

Polycythaemia rubra vera (PRV)

Review FBC, blood film, red cell mass. Bone marrow aspiration and trephine biopsy may sometimes be useful in documenting other features of a true myeloproliferative disorder.

Presence "invitro" of the formation of spontaneous erythroid colonies (SEC's) in the absence of EPO is a sensitive but not specific finding in PRV.

Low EPO is of high diagnostic specificity for PRV.

Positivity for JAK-2 mutation confirms a myeloproliferative disorder.