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Janus kinase 2 Mutation, Quantitative
|Test code||MOLT (Order in Apex as 'Miscellaneous Outside Lab Test' using the complete test name above)|
|Method||PCR & Sequencing|
|Collection Instructions||Due to limited sample stability, collect samples Monday-Thursday only and avoiding holidays.
Record date and time of collection on the tube label
|Container type||Lavender top, Dark green top|
|Amount to Collect||5 mL blood|
|Sample type||Whole blood|
|Preferred volume||5 mL|
|Min. Volume||4 mL|
|Processing notes||Do not centrifuge or aliquot. Ship whole blood to China Basin at ambient temperature.|
|Synonyms||V617F; Myeloproliferative disorders; MPD; JAK2|
|Stability||Room temperature or refrigerated 3 days|
|Additional information||Clinical Significance:
A somatic mutation in a highly conserved residue of the Janus kinase (JAK2) on chromosome 9 was detected in 80% of patients with polycythemia vera(PV), and 30-50% of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). This point mutation in exon 14 of JAK2 alters codon 617 from a valine to a phenylalanine residue on JH2 domain of JAK2 kinase, thus disrupting auto-inhibitory property of this pseudokinase domain and leading to constitutive activation of the tyrosine kinase. This enhanced JAK2 kinase activity is thought to confer erythropoietin hypersensitivity and erythropoietin independent survival to the myeloid stem cells. Although JAK2 V617F mutation has been detected in variable percentage of patients with other type of myeloid malignancies, normal individuals tested so far are exclusively negative for the mutation.
A negative result does not rule out the presence of V617F at a level below the sensitivity of this assay and does not exclude the presence of other mutations in the JAK2 gene.
The Quantitative measurement of V617F may be useful for assessing the correlation of tumor load/phenotype; monitoring/predicting the progression or responses of the disease when MPD patients are under therapy.
|CPT coding||83891-90, 83896-90 83898-90, 83904-90, 83912-90|
|Last Updated||8/7/2014 9:57:24 AM|