Get in touch
Our Client Services team is on hand to help. Please call us at 866.776.5907, Option 3.
MPN JAK2 V617F with Sequential Reflex to JAK2 Exon 12-15, CALR, and MPL
- NGS
This next-generation sequencing (NGS)–based assay is performed as a sequential reflex panel for the evaluation of key driver mutations in myeloproliferative neoplasms (MPN). Testing begins with JAK2 V617F (exon 14) and, if negative, reflexes to JAK2 exons 12–15 , followed by CALR exon 9, and then MPL exon 10. The reflex pathway is discontinued once an informative pathogenic mutation is identified and downstream molecular analyses are not performed; if no mutation is detected, all four targets are reported as negative. Tests may also be ordered individually. Note: This assay replaces the former MPN JAK2 V617F with Sequential Reflex to JAK2 Exon 12-13, CALR, and MPL performed by PCR/fragment analysis/bi-directional sequencing. NY samples are still processed by PCR/fragment analysis/bi-directional sequencing until further notice.
Clinical Significance
Identification of myeloproliferative neoplasm (MPN)-associated driver mutations is important in the diagnosis, prognosis and therapy selection of BCR-ABL1-negative MPN. JAK2 V617F represents the canonical exon 14 gain-of-function mutation, which has been reported in >95% of patients with polycythemia vera (PV) and approximately 50-60% of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). High JAK2 V617F variant allele fraction (>50%) is more commonly observed in PV and is associated with increased risk of myelofibrotic progression in both PV and ET. Targeted therapy directed at the JAK2 V617F mutation is available. A small subset of PV patients that are JAK2 V617F mutation negative will harbor JAK2 mutations in exon 12, usually small in-frame deletions or insertions. JAK2 exon 12 mutated PV shows similar prognosis to JAK2 V617F mutated cases. Other rare non-V617F mutations can be detected in exons 13, 14 and 15 of the JAK2 gene. Somatic insertions or deletions in exon 9 of CALR gene are detected in 25-35% of patients with ET and PMF. The most common CALR mutations observed include a 52bp deletion (type 1) or 5bp insertion (type 2). PMF patients with mutated CALR have a lower risk of thrombosis and longer overall survival than patients with JAK2 and MPL mutation, however, the association may be limited to those with type 1or type 1-like mutation. Exon 10 MPL mutations, most commonly W515 and S505, are present in approximately 5-10% of patients with PMF and ET. MPL and CALR mutations have been associated with increased risk of MF transformation in ET cases. (References: PMID: 35767897, 35732831, 36347013, 37357958, 27187622, 29274140, 26473532, and 38269572)
Specimen Requirements
Bone Marrow Aspirate: 1-2 mL in EDTA tube. Sodium Heparin is acceptable. Peripheral Blood: 3-5 mL in EDTA tube. Sodium Heparin is acceptable. Note: Test is DNA-based. Please select Extract & Hold - DNA if specimen hold service is desired.
Storage and Transportation
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. For fresh samples: refrigerate before shipping and ship same day as drawn whenever possible. Do not freeze.
CPT Code(s)*
81270, 81279, 81219, 81339
*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.
Last Updated: October 13, 2025