Canterbury DHB

Context

Investigation of Suspected PV

An algorithm for investigating suspected PV is suggested on UpToDate – Diagnostic approach to the patient with polycythemia. Bone marrow aspirate, trephine and cytogenetics are not required to diagnose PV, but may be useful in distinguishing between early PV, essential thrombocythemia (ET) (both of which can be associated with thrombocytosis), and early-stage primary myelofibrosis (PMF).

For a discussion of the role of bone marrow histopathology in MPN, see Thiele J, et al. (2005) pages 184–953.

The British Committee for Standards in Haematology4 suggests a similar diagnostic approach.

Note – Red cell mass and endogenous erythroid colony studies are not locally available. A study from the Mayo Clinic found raised red cell mass in all patients with Hct >0.55 and ).50 in men and women respectively.

Non-PV erythrocytosis

If no JAK2 mutation can be found, and serum epo is normal to elevated, PV is virtually excluded. Consider other causes of erythrocytosis:

In patients who have had PV excluded, erythrocytosis may be categorised as:

In such cases, management is directed at the underlying cause so is not typically managed in a haematology clinic. Most patients without PV do not require venesection unless symptomatic, or unless haematocrit is >0.6.

Individualise management for patients with very high haematocrits and, if attempting venesection, monitor treatment closely to ensure it is proving beneficial.

Venesection has not been shown to reduce stroke risk in patients with increased red cell mass secondary to cyanotic heart disease5. By extrapolation, no benefit is expected in patients with elevated red cell mass due to hypoxia in other situations, e.g. smokers.

About this Canterbury DHB document (6654):

Document Owner:

Sean Macpherson (see Who's Who)

Issue Date:

August 2018

Next Review:

April 2021

Keywords:

Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document. Disclaimer

Topic Code: 6654