Diagnostic criteria for MPN-U
| 1. Clinical and hematological features of an MPN are present* |
| 2. JAK2, CALR, or MPL mutation† or presence of another clonal marker‡ |
| 3. Diagnostic criteria for any other MPN, MDS, MDS/MPN,§ or BCR::ABL1-positive CML are not met |
| The diagnosis of MPN-U requires all 3 criteria. |
| 1. Clinical and hematological features of an MPN are present* |
| 2. JAK2, CALR, or MPL mutation† or presence of another clonal marker‡ |
| 3. Diagnostic criteria for any other MPN, MDS, MDS/MPN,§ or BCR::ABL1-positive CML are not met |
| The diagnosis of MPN-U requires all 3 criteria. |
In cases presenting with BM fibrosis reactive causes must be excluded, in particular BM fibrosis secondary to infection, autoimmune disorder or another chronic inflammatory condition, hairy cell leukemia or another lymphoid neoplasm, metastatic malignancy, or toxic (chronic) myelopathy.
It is recommended to use highly sensitive assays for JAK2 V617F (sensitivity level < 1%) and CALR and MPL (sensitivity level 1% to 3%); in negative cases, consider searching for noncanonical JAK2 and MPL mutations.
Assessed by cytogenetics or sensitive NGS techniques; detection of mutations associated with myeloid neoplasms (eg, ASXL1, EZH2, IDH1, IDH2, SF3B1, SRSF2, and TET2 mutations) supports the clonal nature of the disease.
In cases presenting with myelodysplastic features effects of any previous treatment, severe comorbidity, and changes during the natural progression of the disease process must be carefully excluded.