The 2014 BCSH criteria and the 2016 WHO criteria for essential thrombocythemia: A comparison in a large-scale cohort.

OBJECTIVE: There are currently 2 representative diagnostic criteria for essential thrombocythemia (ET), the 2014 British Committee for Standards in Hematology Guidelines (BCSH) criteria and the 2016 World Health Organization (WHO) criteria. We compare and discuss the advantages and disadvantages of the 2 criteria. METHOD: We applied the 2 criteria to 403 patients with thrombocytosis and suspected myeloproliferative neoplasms (MPN) and compared patient populations. RESULTS: The BCSH criteria diagnosed ET in 279 patients (BCSH-ET) whereas the WHO criteria diagnosed ET in 203 patients (WHO-ET). There were 83 patients diagnosable only by the BCSH criteria (BCSH-only-ET), of which under the WHO classification, 69 patients fell under the category of MPN, unclassifiable (MPN-u), 12 patients were PMF, prefibrotic/early stage (pre-PMF), and 2 patients were polycythemia vera. Patient characteristics such as age, hemoglobin, hematocrit, platelet counts, lactate dehydrogenase levels, JAK2V617F allele burdens, prevalence of myelofibrosis and splenomegaly, and frequencies of thrombotic events and treatment did not differ between WHO-ET and BCSH-only-ET, but BCSH-only-ET patients showed higher WBC counts and higher JAK2V617F mutation frequencies. CONCLUSION: The BCSH criteria diagnosed ET in a broader range of patients encompassing a significant number of patients who would otherwise be diagnosed as pre-PMF or MPN-u.