Table 2.
Clinical Indications for Screening JAK2 and MPL Mutations
| Mutation | Screening appropriate | Not indicated |
|---|---|---|
| JAK2V617F | Erythrocytosis | For purposes of MPN prognostication |
| Thrombocytosis | To differentiate one MPN from another | |
| Bone marrow fibrosis | Testing both blood and bone marrow | |
| BCR-ABL1-negative granulocytosis | ||
| Unexplained monocytosis | ||
| Unexplained splenomegaly | ||
| Aquagenic pruritus | ||
| Splanchnic vein thrombosis | ||
| Testing either blood or bone marrow | ||
| JAK2 exon 12 mutation | JAK2V617F-negative erythrocytosis and low Epo | Before JAK2V617F screening |
| Suspected JAK2V617F-negative post-PV MF | In the presence of JAK2V617F | |
| For diagnosis of ET or PMF | ||
| MPL mutation | Thrombocytosis and morphologically equivocal for ET | For diagnosis of PV Morphologically confirmed ET or PMF |
| Marrow fibrosis and morphologically equivocal for PMF | JAK2V617F positive |
Epo, serum erythropoietin level; MF, myelofibrosis.