Canterbury DHB


Diagnostic Criteria

For WHO 2016 diagnostic criteria for ET, see Arber DA, et al. (2016),1 table 5, page 5.

To diagnose ET, either all the major criteria, or the first 3 major criteria and the minor criterion, are met. A diagnosis can therefore be made without a bone marrow biopsy; however, a biopsy can help distinguish ET from primary myelofibrosis (PMF), in particular. PMF and ET have very different prognosis and overall survival, so this distinction is important – especially in younger patients.

For additional information on morphologic features of ET, see the 2016 WHO classification of tumours of haematopoietic and lymphoid tissues,2 pages 50–53.

Prior to molecular testing or bone marrow biopsy, try to exclude reactive causes of thrombocytosis, such as:

About this Canterbury DHB document (6237):

Document Owner:

Bridgett McDiarmid (see Who's Who)

Last Reviewed:

August 2018

Next Review:

April 2021


Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document. Disclaimer

Topic Code: 6237