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Beaumont Laboratory

MPL Gene Mutation

ET, essential thrombocytosis, thrombocythemia, PMF, primary myelofibrosis, fibrosis, MPN, myeloproliferative neoplasm, EPIC: LAB6393, SOFT: GMPLG

Specimen Collection Criteria

Collect: One of the following specimens:

  • Peripheral Blood: 10 mL whole blood in Lavender-top EDTA or Yellow-top ACD tubes. (Min: 5.0 mL)
  • Bone Marrow Aspirate: 1.0 mL bone marrow in a Lavender-top EDTA tube. (Min: 0.5 mL) 

FedEx Shipping Instructions

Transport 10 mL whole blood (minimum: 5 mL) or 1.0 mL bone marrow aspirate (minimum: 0.5 mL), refrigerated. Do not freeze specimens.

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Physician Office/Drawsite Specimen Preparation

Do not freeze specimens. Maintain whole blood or bone marrow at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: 10 mL whole blood (Min: 5.0 mL) or 1.0 mL bone marrow (Min: 0.5 mL), at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

  • Frozen specimens. (Freezing causes lysis of RBCs and release of hemoglobin, which inhibits PCR.)
  • Unlabeled tubes.
  • Specimens collected in heparin (Green-top), clot tubes (Red-top), or SST tubes. 


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 72 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Royal Oak Clinical Molecular Pathology Laboratory.


Results available within 14 days.

Reference Range

Negative for MPL mutations.

Test Methodology

Real-Time Polymerase Chain Reaction (PCR) with Allelic Discrimination.


This test detects the W515L and W515K mutations in the MPL gene. The MPL gene is a member of the hematopoietin gene superfamily and encodes the thrombopoietin receptor, facilitating global hematopoiesis and megakaryocyte growth and differentiation. The MPL mutations are gain of function mutations and induce initiating events in myeloproliferative neoplasms.

Clinical Utility

  • MPL mutations have been reported in JAK 2 negative myeloproliferative neoplasms; 5-8% of patients with primary myelofibrosis and 1-3% of patients with essential thrombocythemia are positive for MPL mutations. Therefore detection of MPL mutations facilitates the diagnosis of myeloproliferative neoplasms and aids in patient monitoring, representing a useful clonal marker.
  • The test is recommended in patients with BCR/ABL1 and JAK2 negative myeloproliferative neoplasms to aid in diagnosis and monitoring the malignant clone.

CPT Code


Test Codes


Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.