Myelofibrosis IWG-MRT prognostic score for myelofibrosis Applies at the time of diagnosis. Value 1. Sum the number of adverse prognostic factors Age (years)* Age > 65 y WBC count (x 109/L)* Constitutional symptoms Hemoglobin (x g/dL)* Hemoglobin <10 g/dL Peripheral blood blasts (% of leukocytes)* WBC count > 25 × 109/L Constitutional symptoms -Please Select No Yes Circulating blasts >1% 2. Determine IWG-MRT risk group and prognosis IWG-MRT score Number of factors Risk group Proportion of patients Median OS (m) IWG-MRT risk group 0 Low 22 135 1 Intermediate-1 29 95 2 Intermediate-2 28 48 ≥ 3 High 21 27 Reference Cervantes F, Dupriez B, Pereira A, Passamonti F, Reilly JT, Morra E et al. New prognostic scoring system for primary myelofibrosis based on a study of the International Working Group for Myelofibrosis Research and Treatment. Blood 2009; 113: 2895-2901.