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Referral
Thrombocytosis (High Platelets)
Scope
Thrombocytosis is an increase in platelets more than 500 x 10 9/L, commonly found incidentally in a routine blood test.
There are broadly two types of thrombocytosis:
Primary haematological disease:
- Essential thrombocythaemia (also referred to as primary thrombocytosis). The clinical features can relate to an increased incidence of arterial and venous thrombosis and bleeding. Most can remain well for decades.
- Polycythaemia vera
- Primary myelofibrosis
- Chronic myeloid leukaemia
- Myelodysplastic syndromes
Secondary or reactive (changes are caused by an exaggerated physiological response to a primary problem):
- infectious disease
- inflammatory disease
- neoplasms
- non-malignant haematological conditions e.g. acute blood loss, iron deficiency anaemia
- functional and surgical hyposplenism
- tissue damage, e.g. recent trauma or surgery
- exercise
- reaction to medications e.g. steroids, adrenalin
- pregnancy
- allergic reactions
Signs and Symptoms
- History of arterial or venous thromboembolism or bleeding
- Look for inflammatory, infective, or neoplastic conditions
- Examine for splenomegaly
History and Examination
- History of arterial or venous thromboembolism or bleeding
- Full Blood Count
- Ferritin
- C-reactive Protein (CRP)
- If haematocrit (Hct) is elevated or splenomegaly, consider primary polycythaemia vera and request haematology assessment
- If haematocrit is normal and no splenomegaly, repeat full blood count, ferritin, and CRP in 2 to 3 weeks
- If ferritin is low, consider iron deficiency.
- Thrombocytosis is most likely to be reactive if:
- platelets normalise with time
- platelets and CRP remain elevated (ferritin may be raised)
- if underlying reactive condition present (see list above)
- If platelets remain more than 500 x 109/L but CRP and ferritin are normal, it is likely to be essential thrombocythaemia and request haematology assessment.
Referral Criteria
- Request haematologist assessment if platelets remain more than 500 x 109/L.
- Where appropriate, written advice may also be available
Referral Instructions
e-Referral Service Selection
Specialty: Haematology
Clinic Type: Not otherwise specified
Service: DRSS-Western-Haematology-Devon ICB-15N
Referral Form
Pathway Group
This guideline has been signed off on behalf of NHS Devon.
Publication date: July 2016
