Interpretation
The acquisition of a JAK2 V617F mutation within an erythroid/myeloid progenitor is associated with many (but not all) myeloproliferative disorders: polycythaemia vera (96% cases), essential thrombocythaemia (60-65% cases) and primary myelofibrosis (60-65% cases).
Patients negative for a JAK2 V617F variant : for those with erythrocytosis and low erythropoietin (typically <5 mIU/ml) consider JAK2 exon 12 mutation analysis and for those with essential thrombocythaemia or primary myelofibrosis consider calreticulin and MPL mutation analysis.
Reference Intervals
Result reported as “Detected” or “Not detected”. If mutation is detected the % mutant load (% mutant copies over total JAK2 gene copies) is reported.
Test Method
Droplet digital PCR using the Bio-Rad PrimePCR ddPCR Mutation Detection Assay for JAK2 p.Val617Phe [NM_004972.3 (JAK2):c.1849G>T (p.Val617Phe)].
Limit of Detection: 0.1% mutant copies over total JAK2 gene copies.