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Alternative Name
Myeloproliferative Leukemia
Test Description

Bi-directional sequencing of exon 10 of the MPL gene to detect all possible mutations at the W515 and S505 codons, and other mutations throughout the exon. Testing is performed on plasma for increased sensitivity whenever possible. This test may be ordered separately or as part of the MPN Reflex Panel. Testing is approved for specimens from the state of New York.

Clinical Significance

MPL W515 mutations are present in JAK2-negative patients with primary myelofibrosis (PMF) or essential thrombocythemia (ET) at a frequency of approximately 1-5%, respectively. The S505 mutation is usually detected in patients with familial essential thrombocythemia.  Mutation analysis helps differentiate reactive conditions from MPNs.

Specimen Requirements
  • Peripheral blood: 5 mL in EDTA tube.
  • Bone marrow: 2 mL in EDTA tube.
Storage and Transportation

Use cold pack for transport, making sure cold pack is not in direct contact with specimen. Ship same day as drawn whenever possible; specimens <72 hours old preferred.

CPT Code(s)*
81339 (as of 01/01/2021); Prior to CPT Code was 81402
New York Approved
Level of Service
Turnaround Time

10 days

*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.