What are the stages of myelofibrosis?

Myelofibrosis doesn’t have a formal staging system. Instead, myelofibrosis is graded by the degree of fibrosis (or scarring) evident in the bone marrow. Various medical parameters including the degree of marrow fibrosis, blood cell count abnormalities, symptoms and molecular/genetic features of the malignant cells are used to help physicians identify those patients at greatest risk for problems.