Rationale

A focused history helps distinguish primary clonal erythrocytosis such as PV from secondary causes (such as hypoxia or exogenous erythropoietin stimulation)^1,2

• a – d: assess for hypoxia-driven or medication-related secondary causes.

• e – g and j: are typical symptoms associated with polycythemia vera and other myeloproliferative neoplasms.

Rationale

Serum erythropoietin level and JAK2 mutation testing are appropriate initial investigations
when PV is suspected.

According to the WHO diagnostic criteria for PV:

Major criteria:

1. Elevated Hb/Hct  
2. Bone marrow panmyelosis  
3. JAK2 mutation  

Minor criterion:  

• Subnormal serum EPO  

The diagnosis of PV usually requires either all 3 major criteria or the first 2 major criteria plus the minor criterion.^1,3 

Although bone marrow (BM) biopsy is one of the major WHO diagnostic criteria, it is not the most appropriate initial test because JAK2 mutation testing and serum erythropoietin level are less invasive, rapidly available, and sufficient to establish a provisional diagnosis. BM biopsy may not be required in cases with sustained absolute erythrocytosis if major criterion 3 and the minor criterion are present. Myelofibrosis, however, which may be present at diagnosis, can only be detected with a BM biopsy, so is usually performed.^1,3 


Abdominal ultrasound, sleep study and arterial blood gas, though not required for the diagnosis of PV, may help identify other causes of erythrocytosis.²

Rationale

Risk stratification refers to risk of thrombosis – progression risk is separate from thrombotic risk.¹

John is considered low risk based on his age (<60) and no prior thrombosis, however, once he turns 60 he will be considered high risk. Increasing age is a continuous risk factor for thrombosis.^5,6

PV patients defined as low risk still have a greater thrombotic risk than the general population.^5,6 

Rationale

Current drug therapy in PV targets thrombosis and PV-related symptoms but has not been shown to prevent disease transformation. Therapy is often individualized to balance efficacy and treatment-related risks.^5,7 

Rationale

Clinicians frequently under‑recognize symptoms⁸, and patients benefit when asked directly about daily impact, emotional burden, and understanding of their results.⁹

Symptom tracking may improve accuracy¹⁰ and engagement.¹¹

These approaches align with best practice recommendations for improving shared decision‑making.¹¹

Rationale

PV increases the risk of both arterial and venous thrombosis due to increased blood viscosity.^1,5,6

It is also associated with hyperuricemia from increased cell turnover (causing gout)¹²,
and long‑term risk of progression to post‑PV myelofibrosis or acute myeloid leukemia.^1,5

Plasma cell dyscrasia is not associated with PV.

Rationale

Higher thrombotic risk is associated with previous thrombosis , Age, Hct>45% and CV comorbidities, including smoking and hypertension.⁶

JAK2 V617F allele frequency >50% is associated with high risk for venous, but not arterial, thrombosis.⁶

There is no clear correlation between thrombocytosis and thrombosis risk in PV, though leukocytosis is associated with increased thrombotic risk.⁶

Rationale

Studies using MPN-SAF demonstrate that symptom burden may persist despite hematologic control.¹³

Rationale

PV patients frequently have traditional CV risk factors which contribute to CV events and overall mortality. There are currently no PV-specific CV risk reduction recommendations, so lifestyle modification advice should follow general high CV risk guidelines.⁶ 

High‑dose antioxidant supplements have no evidence for CV benefit in any population and are not recommended.¹⁴