Clinical utility of investigations in triple-negative thrombocytosis: A real-world, multicentre evaluation of UK practice.
Godfrey AL., Sousos N., Frewin R., Prahladan M., Green AC., McGregor A., Khan A., Milne K., Amin F., Torre E., Gudgin EJ., Lambert J., Wilson AJ., Royston D., Harrison CN., Mead AJ.
Diagnosis of essential thrombocythaemia (ET) is challenging in patients lacking JAK2/CALR/MPL mutations. In a retrospective evaluation of 320 patients with 'triple-negative thrombocytosis', we assessed utility of bone marrow histology (90.9% of patients) and myeloid gene panel (MGP, 55.6%). Supportive histology ('myeloproliferative neoplasm-definite/probable', 36.8%) was associated with higher platelet counts and varied between centres. 14.6% MGP revealed significant variants: 3.4% JAK2/CALR/MPL and 11.2% other myeloid genes. Final clinical diagnosis was strongly predicted by histology, not MGP. 23.7% received cytoreduction (17.6% under 60 years). Real-world 'triple-negative' ET diagnosis currently depends heavily on histology; we advocate caution in MGP-negative cases and that specific guidelines are needed.