Clinical investigations from the RACP

Investigating thrombocytosis

Clinical investigations from the RACP

Investigating thrombocytosis

Pauline Warburton

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Abstract

There are many possible causes for thrombocytosis. Usually the thrombocytosis is reactive rather than being due to a primary haematological disorder, and in most cases the cause will be obvious and readily determined without the need for extensive investigations.

Key Points

  • Thrombocytosis is more often reactive than due to a primary haematological disorder.
  • Diagnosing the cause of thrombocytosis is important to enable appropriate management.
  • The cause of thrombocytosis can often be determined by reviewing previous full blood counts, considering any other abnormalities on the full blood count and taking a detailed history.
  • There are a small number of patients with thrombocytosis in whom the cause will remain uncertain.
  • Some laboratory tests may assist in difficult cases; however, there is none that will definitely differentiate reactive from autonomous thrombocytosis.
  • Patients with a primary haematological disorder and those in whom the diagnosis has not been determined should be referred to a haematologist.