Test ID: JAK2M JAK2 V617F Mutation Detection, Bone Marrow
Reporting Name
JAK2 V617F Mutation Detection, BMUseful For
Aiding in the distinction between a reactive blood cytosis and a chronic myeloproliferative disorder in bone marrow specimens
Testing Algorithm
See Myeloproliferative Neoplasm: A Diagnostic Approach to Bone Marrow Evaluation in Special Instructions.
Specimen Type
Bone MarrowShipping Instructions
Specimen must arrive within 7 days of collection.
Specimen Required
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD)
Specimen Volume: 2 mL
Collection Instructions:
1. Invert several times to mix bone marrow.
2. Send specimen in original tube.
Specimen Minimum Volume
1 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Bone Marrow | Ambient (preferred) | 7 days | PURPLE OR PINK TOP/EDTA |
Refrigerated | 7 days | PURPLE OR PINK TOP/EDTA |
Special Instructions
Reference Values
An interpretive report will be provided.
Day(s) and Time(s) Performed
Monday through Friday; 12 p.m.
CPT Code Information
81270-JAK2 (Janus kinase 2) (eg, myeloproliferative disorder) gene analysis, p.Val617Phe (V617F) variant
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
JAK2M | JAK2 V617F Mutation Detection, BM | 72333-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
39723 | JAK2 Result | 53761-3 |
31157 | JAK2 V617F Mutation Detection, BM | 72333-8 |
Clinical Information
The Janus kinase 2 gene (JAK2) codes for a tyrosine kinase (JAK2) that is associated with the cytoplasmic portion of a variety of transmembrane cytokine and growth factor receptors important for signal transduction in hematopoietic cells. Signaling via JAK2 activation causes phosphorylation of downstream signal transducers and activators of transcription (STAT) proteins (eg, STAT5) ultimately leading to cell growth and differentiation. BCR-ABL1-negative myeloproliferative neoplasms (MPN) frequently harbor an acquired single nucleotide variant in JAK2 characterized as c.G1849T; p. Val617Phe (V617F). This variant is identified overall in approximately two-thirds of all MPN,(1-3) but the prevalence varies by MPN subtype. The JAK2 V617F variant is present in 95% to 98% of polycythemia vera patients, 50% to 60% of primary myelofibrosis (PMF) patients, and 50% to 60% of essential thrombocythemia (ET) patients. It has also been described infrequently in other myeloid neoplasms, including chronic myelomonocytic leukemia and myelodysplastic syndrome.(4) This variant is not seen in chronic myelogenous leukemia (CML) or in reactive conditions with elevated blood counts. Detection of the JAK2 V617F variant is useful to help establish the diagnosis of MPN. However, a negative JAK2 V617F result does not indicate absence of a MPN. Other important molecular markers in BCR-ABL1-negative MPN include CALR exon 9 variant (20%-30% of PMF and ET) and MPL exon 10 variant (5%-10% of PMF and 3%-5% of ET). Variants in JAK2, CALR, and MPL are essentially mutually exclusive.
Interpretation
The results will be reported as 1 of the 2 states:
-Negative for JAK2 V617F variant
-Positive for JAK2 V617F variant
Positive variant status is highly suggestive of a myeloid neoplasm, but must be correlated with clinical and other laboratory features for definitive diagnosis.
Negative variant status does not exclude the presence of a myeloproliferative neoplasm or other neoplasm.
Results below the laboratory cutoff for positivity are of unclear clinical significance at this time.
Clinical Reference
1. Baxter EJ, Scott LM, Campbell PJ, et al: Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders. Lancet 2005 March 16;365(9464):1054-1061
2. James C, Ugo V, Le Couedic JP, et al: A unique clonal JAK2 mutation leading to constitutive signaling causes polycythaemia vera. Nature 2005 April 28;434(7037):1144-1148
3. Kralovics R, Passamonti F, Buser AS, et al: A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 2005;352:1779-1790
4. Steensma DP, Dewald GW, Lasho TL, et al: The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both "atypical" myeloproliferative disorders and the myelodysplastic syndrome. Blood 2005;106(4):1207-1209
5. Gong, Jerald Z, Cook, James R, et al: Laboratory Practice Guidelines for Detecting and Reporting JAK2 and MPL Mutations in Myeloproliferative Neoplasms. J Mol Diag 2013;15(6):733-744
Analytic Time
2 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.Method Name
Point Mutation Detection in DNA using Quantitative Polymerase Chain Reaction (PCR)
Forms
1. Hematopathology Patient Information (T676) in Special Instructions
2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.
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