Thrombocytosis/Thrombocythaemia

DGRefHelp - NHS Dumfries & Galloway
NHS Dumfries and Galloway

Defined as persistent platelet count >400. Thrombocytosis is commonly a reactive and transient phenomenon

Causes

  • Reactive: infection, inflammation, iron deficiency / trauma, hyposplenism, neoplasia, connective tissue disorders, steroids
  • Primary: Myeloproliferative Neoplasia, certain Myelodysplastic Syndrome subtypes

Assessment

  • History and examination ( bleeding, weight loss, GI symptoms, active arthritis)
  • Repeat FBC 4 weeks following the initial result, blood film examination will be added on by the lab if appropriate
  • Serum Ferritin / iron studies, CRP
  • Other testing to be guided by clinical findings

Who to refer

Urgent referral

  • Unexplained platelet count >1000
  • Unexplained platelet count >450 in individuals who sustained arterial or venous thrombosis ( DVT/PE, TIA/CVA, Angina / MI) or abnormal bleeding

Routine referral

Persistent unexplained thrombocytosis (platelet count >450) over at least 3 months period

The haematology team might advise that a blood sample in EDTA Tube shall be sent for molecular testing (JAK2, CALR mutation analysis) when the  case is referred to haematology for suspected Myeloproliferative Neoplasia, and the team might suggest waiting for resuls prior to assessing patient.

Who not to refer

A referral to haematology is not indicated in cases of persistent mild thrombocytosis where a cause is identifiable. Anti-platelet therapy can be considered on individual case basis after discussion with haematology.

Editorial Information

Last reviewed: 01/10/2024

Next review date: 01/10/2026

Author(s): Muayed Lasebai, Ranjit Thomas, Paul Ames.

Version: 1.0