Required section · Section 4 of 6
Guided example: rank the evidence
The case serum erythropoietin (EPO) is 2.4 mU/mL against a local interval of 2.6-18.5 mU/mL. JAK2 V617F, a valine-to-phenylalanine variant at codon 617 of JAK2, is detected by the local validated assay. The case provides no reactive explanation in the supplied history.
The persistent erythrocytosis, thrombocytosis, mild neutrophilia, low EPO context, and JAK2 result support an integrated PV workup. Low EPO supports autonomous erythroid production because autonomous red-cell production suppresses normal renal EPO feedback. JAK2 V617F supports clonality across PV, ET, and PMF; it is not entity-specific. The absence of nucleated red cells, teardrops, and left shift does not demonstrate leukoerythroblastosis or PMF morphology.
PV marrow is generally hypercellular for age with trilineage proliferation and pleomorphic megakaryocytes without marked atypia. Marrow morphology and the local clinical diagnostic pathway remain needed to apply the declared framework. Communicate the verified pattern and molecular result with their method limits for controlled classification review.
Illustrative drawing — this picture was drawn rather than captured.
| Finding | Interpretation | Limitation |
|---|---|---|
| Persistent high hemoglobin and platelets | Supports a true sustained pattern | Does not establish cause |
| Low erythropoietin | Supports PV context | Not diagnostic alone |
| JAK2 V617F detected | Supports clonality | Not specific to PV |
| No teardrops or nRBCs | Argues against this film showing leukoerythroblastosis | Does not exclude PMF by itself |
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