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Test Code CALR CALR Mutation Analysis, Myeloproliferative Neoplasm (MPN), Varies

Reporting Name

MPN, CALR Gene Mutation, Exon 9

Useful For

Rapid and sensitive detection of insertion and deletion-type mutations in exon 9 of CALR


An aid in distinction between reactive thrombocytosis and leukocytosis versus a myeloproliferative neoplasm (MPN), especially essential thrombocythemia (ET) and primary myelofibrosis (PMF), and is highly informative in cases in which JAK2 and MPL testing are negative


Especially helpful to the pathologist in those bone marrow cases with ambiguous etiology of thrombocytosis, equivocal bone marrow morphologic findings of MPN, and unexplained reticulin fibrosis


An aid in prognostication of PMF and thrombosis risk assessment in ET

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Shipping Instructions

Specimen must arrive within 7 days (168 hours) 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: Peripheral blood

Container/Tube: EDTA (lavender top) or ACD-B (yellow top)

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: Ambient (preferred)/Refrigerate


Specimen Type: Bone marrow

Container/Tube: EDTA (lavender top) or ACD-B (yellow top)

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: 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 include indication of volume and concentration of the DNA.

Specimen Stability: Frozen (preferred)/Refrigerate/Ambient

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies 7 days

Reference Values

An interpretive report will be provided

Day(s) and Time(s) Performed

Monday through Friday; 8 a.m.

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

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

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CALR MPN, CALR Gene Mutation, Exon 9 77174-1


Result ID Test Result Name Result LOINC Value
MP020 Specimen 31208-2
36301 Final Diagnosis 22637-3

Clinical Reference

1. Klampfl T, Gisslinger H, Harutyunyan AS, et al: Somatic mutation of calreticulin in myeloproliferative neoplasms. N Engl J Med 2013;369:2379-90

2. Nangalia J, Massie CE, Baxter EJ, et al: Somatic CALR mutation in myeloproliferative neoplasms with nonmutated JAK2. N Engl J Med 2013;369:2391-2405

3. Rumi E, Pietra D, Ferretti V, et al: JAK2 or CALR mutation status defines subtypes of essential thrombocythemia with substantially different clinical course and outcomes. Blood 2014 Mar 6;123(10):1544-1551

4. Rotunno G, Mannarelli C, Guglielmelli P, et al: Impact of calreticulin mutations on clinical and hematological phenotype and outcome in essential thrombocythemia. Blood 2014;123(10):1552-1555

5. Tefferi A, Lasho TL, Finke CM, et al: CALR vs JAK2 vs MPL-mutated or triple-negative myelofibrosis: clinical, cytogenetic and molecular comparisons. Leukemia 2014 Jul;28(7):1472-1477

Method Description

PCR amplification of CALR exon 9 is performed on DNA isolated from the patient sample. The PCR product is then run on an ABI 3130xl Genetic Analyzer for fragment analysis to detect insertions and deletions. An unmutated CALR will show an amplicon at 266 bp, a mutated CALR with insertion will show an amplicon greater than 266 bp, and a mutated CALR with deletion will show an amplicon smaller than 266 bp. This assay has an analytical sensitivity of approximately 6% (ie, 6 mutation-containing cells in 100 total cells) in most mutation types, except for the rare type of 1-bp deletion, which has a sensitivity of approximately 20%. This is a laboratory developed test using analyte-specific reagents and research use only (RUO) reagents.(Unpublished Mayo method)

Analytic Time

3 days

Reject Due To

Gross hemolysis Reject
Other Paraffin-embedded bone marrow aspirate clot Bone marrow biopsies, slides, or paraffin shavings Moderately to severely clotted

Method Name

Polymerase Chain Reaction (PCR) and Fragment Analysis


1. Hematopathology Patient Information (T676) in Special Instructions

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