Investigation and Referral Guidance


Refer through Choose and Book If

1)         Haematocrit (HCT) ³0.52 males, ³0.48 females


There are other features to suggest a myeloproliferative disorder


There is a recent thrombotic or embolic history



2)         Haematocrit (HCT) ³0.52 males, ³0.48 females sustained for > 3 months


                There are NO causes of secondary or relative polycythaemia present


When criteria in 2) are met our clinical advisory service (through C+B) will advise whether JAK2 and erythropoietin (epo)  test should be performed  before attendance. These tests require approval.


JAK2:a separate EDTA (full blood count style) specimen to haematology recording in the history that the test has been approved. JAK2 is positive in 95% of primary polycythaemia.


Epo:  yellow top (biochemistry style)specimen to haematology.


Secondaryis common.

It is usually driven by excess epo due to hypoxia, or rarely an epo producing tumour.


Causes include


Chronic exposure to carbon monoxide including smoking

Cardiac failure

Sleep apnoea / massive obesity

Testosterone replacement, and anabolic steroid and erythropoietin misuse
Cyanotic heart disease or pulmonary shunt

Tumours include fibroids, renal cell carcinoma, hepatoma, and phaeochromocytoma


Relative(reduced plasma volume) is common.

Causes Include


Obesity with hypertension


Excess alcohol or dehydrating beverages (eg frequent strong coffee)



Primary(myeloproliferative)is rare (incidence 1 / 50,000) and is suggested by:

Pruritus after bathing


Raised RBCs but with hypochromic indices suggesting iron deficient polycythaemia

Platelet count > 400 x 109/l

Unexplained raised total white count.



Recommended initial examination and tests:

History and examination to distinguish potential primary and secondary causes as above.

FBC, repeating at 3 months if necessary
U+E, LFT, Urate, ferritin

CXRand pulse oximetry where appropriate / available.


Initial management

The management of secondary polycythaemia is the management of the underlying disorder.

There is little evidence that COPD patients gain any objective benefit from venesection.

Venesection is not performed in cyanotic heart disease except at the request of the cardiologist.

Where testosterone replacement must be continued it is appropriate to refer for venesection.




Date reviewed               30/6/2019

Next review due             30/6/2020

Sifter name                   Michele Sharkey


Awaiting Consultant Approval


Version 2.2