JAK2 Exon 12, 13, 14, and 15 Mutation Analysis

Message
*Collect specimen Monday through Friday only before 1500 EST. Do not collect the day before a holiday.


Test Code
LAB00110


Alias/See Also
LAB00110
LabCorp TC: 489501
Janus Kinase 2 Exons 12, 13, 14, and 15


CPT Codes
81279

Preferred Specimen
5 mL Lavender (EDTA) - Whole Blood


Minimum Volume
3 mL Lavender (EDTA) - Whole Blood


Other Acceptable Specimens
Dark Green Top (Sodium Heparin) - Whole Blood
Yellow Top (ACD) - Whole Blood
1 mL Bone Marrow


Transport Temperature
Room Temperature


Specimen Stability
Room Temperature - Should arrive in the lab with in 48 hours of collection. Store refrigerated if there will be a delay in transit.


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Specimen does not meet all of the criteria for sample type, container, minimum volume, collection and storage, frozen whole blood or marrow; leaking tube; clotted blood or marrow; grossly hemolyzed or otherwise visibly degraded; contamination by another specimen; specimen containing foreign material.


Methodology
Amplicon-based Next Generation Sequencing

Limitations
This assay has a sensitivity of approximately 1% VAF for JAK2 V617F and 2.5% VAF for other mutations in JAK2 exons 12 to 15.
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.


Clinical Significance
Molecular testing of blood or bone marrow is useful in the evaluation of suspected myeloproliferative neoplasms (MPN). This test will assess mutations in JAK2 exons 12, 13, 14, and 15.

The JAK2 (Janus kinase 2) gene encodes for a non-receptor protein tyrosine kinase that activates cytokine and growth factor signaling. The V617F (c.1849 G>T) mutation results in constitutive activation of JAK2 and downstream STAT5 and ERK signaling. The V617F mutation is observed in approximately 95% of polycythemia vera (PV), 60% of essential thrombocythemia (ET) and primary myelofibrosis (PMF). It is also infrequently present (3-5%) in myelodysplastic syndrome, chronic myelomonocytic leukemia and other atypical chronic myeloid disorders. A small percentage of JAK2 mutation-positive patients (3.3%) contain other non-V617F mutations within exons 12-15. In particular, mutations in exon 12 of JAK2 have been described in approximately 3% of patients with PV. JAK2 mutation allele burden correlates with clinical phenotype, with low levels of mutant allele characterized by thrombocytosis, intermediate levels with erythrocytosis and high mutant allele burden, correlating with enhanced myelopoiesis of the BM, leukocytosis, increasing spleen size and circulating CD34-positive cells. 
 


Performing Laboratory
LabCorp



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.