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Myeloproliferative Neoplasm, JAK2 V617F with Reflex to CALR and MPL, Varies

Important Note

Test subject to Local Coverage Determination (LCD) Molecular Pathology Procedures (L35000).

Please check with the patient’s insurance to determine if prior authorization is required. Reminder- Medicare does not provider prior authorization. If in doubt about the coverage for a Medicare patient, please obtain an ABN.

Additional Codes

Primary ID

Epic Code Mayo Test ID




Useful For

Aiding in the distinction between a reactive cytosis and a chronic myeloproliferative disorder


Evaluating for variants in JAK2, CALR, and MPL genes in an algorithmic process

Testing Algorithm

This reflex test sequentially evaluates for the common major gene variants associated with non-BCR-ABL1-positive myeloproliferative neoplasms until a variant is identified. The testing sequence is based on the reported frequency of gene variants in this disease group. Initial testing evaluates for the presence of the JAK2 V617F variant. If this result is negative or very low positive (0.06%-0.6%), testing proceeds with assessment for CALR  gene variants. If the CALR result is also negative, then testing proceeds to evaluate for variants in exon 10 of the MPL gene. If either JAK2 V617F (>0.6%) or CALR variants are detected in the process, the testing algorithm ends; therefore, the complete reflex is followed only in the event of sequential negative variant. An integrated report is issued with the summary of test results.


The following algorithms are available in Special Instructions:

-Myeloproliferative Neoplasm: A Diagnostic Approach to Bone Marrow Evaluation

-Myeloproliferative Neoplasm: A Diagnostic Approach to Peripheral Blood Evaluation

Reporting Name

MPN (JAK2 V617F, CALR, MPL) Reflex

Specimen Type


Shipping Instructions

Specimen must arrive within 7 days of collection.

Necessary Information

The following information is required:

1. Pertinent clinical history

2. Clinical or morphologic suspicion

3. Date of collection

4. Specimen source

Specimen Required

Submit only 1 of the following specimens:


Specimen Type: Blood

Container/Tube: Lavender top (EDTA) or yellow top (ACD solution B)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

Specimen Stability Information: Ambient (preferred)/Refrigerate


Specimen Type: Bone marrow

Container/Tube: Lavender top (EDTA) or yellow top (ACD solution B)

Specimen Volume: 2 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.

Specimen Stability Information: Ambient (preferred)/Refrigerate


Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions: Label specimen as extracted DNA from blood or bone marrow and provide indication of volume and concentration of the DNA.

Specimen Stability Information: Frozen (preferred)/Refrigerate/Ambient

Specimen Minimum Volume

Blood and Bone marrow: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies 7 days

Reject Due To

Gross hemolysis Reject
Other Paraffin-embedded bone marrow aspirate clot or biopsy blocks Slides Paraffin shavings Moderately to severely clotted

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday through Friday

Analytic Time

7 days

Specimen Retention Time

DNA: 3 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test 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.

CPT Code Information

81270-JAK2 (Janus kinase 2) (eg, myeloproliferative disorder) gene analysis, p.Val617Phe (V617F) variant

81219-CALR (calreticulin) (eg, myeloproliferative disorders), gene analysis, common variants in exon 9 (if appropriate)

81403-MPL (myeloproliferative leukemia virus oncogene, thrombopoietin receptor, TPOR) (eg, myeloproliferative disorder), exon 10 sequence (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MPNR MPN (JAK2 V617F, CALR, MPL) Reflex In Process


Result ID Test Result Name Result LOINC Value
39725 MPNR Result No LOINC Needed
36687 Final Diagnosis 22637-3

NY State Approved


Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CALX CALR, Gene Mutation, Exon 9, Reflex No, (bill only) No
MPLR MPL Exon 10 Mutation Detection, R No, (bill only) No

Method Name

Point Mutation Detection in DNA using Quantitative Polymerase Chain Reaction (PCR)


If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.