Current RMA Instruments
| Reasonable Hypothesis SOP | 87 of 2021 |
| Balance of Probabilities SOP | 88 of 2021 |
Changes from previous Instruments
ICD Coding
- ICD-9-CM Codes: 238.4
- ICD-10-AM Codes: D45
Brief description
This is a blood/bone marrow disorder in which all blood cells (red cells, white cells, platelets) are excessive in number. The adjective ‘vera’ implies that this is the true disorder (primary or idiopathic) rather than a secondary disorder.
This disorder causes an increase in blood viscosity which places a strain on heart functioning and produces a tendency towards clotting (thrombosis). There is increased blood cell turnover, leading to hyperuricaemia.
This condition is one of the chronic Philadelphia chromosome negative myeloproliferative neoplasms. The other conditions in that group are essential thrombocythaemia and primary myelofibrosis. Polycytheamia vera is (now) classified as a malignant neoplasm.
Confirming the diagnosis
This diagnosis is complex and is a diagnosis of exclusion of secondary causes. Testing will typically include a full blood count, a peripheral blood smear and a bone marrow biopsy. Genetic testing is also likely to be done.
WHO diagnostic criteria include:
- an elevated haemoglobin (> 16.5 g/dL in men, > 16 g/dL in women), or haematocrit (> 49% in men, > 48% in women);
- bone marrow biopsy showing hypercellularity and other features
- presence of JAK2V617F or JAK2 exon 12 mutation
[These criteria will be used by clinicans in making the diagnosis but demonstration of these features is not required for DVA purposes - a specialist diagnosis is sufficient.]
The relevant medical specialist is a haematologist.
Additional diagnoses covered by SOP
- Primary polycythaemia
- Polycythaemia rubra vera
Conditions not covered by SOP
- Secondary polycythaemia
- Relative polycythaemia
Clinical onset
Onset can be at any age, including childhood, but the median age of diagnosis is 60 years. It is usually found incidentally following a blood test performed for another reason. There may be non-specific symptoms e.g. headache, dizziness, visual disturbances, pruritus or there may be thrombosis or abnormal bleeding.
Clinical worsening
The only SOP worsening factor is for inability to obtain appropriate clinical management. Modern therapy can relieve symptoms and prolong survival, but is not curative.