Label Name: CALR
Lab Discipline: Molecular Diagnostics
Institution:  Duke University Health System 
EAP ID:  LAB9270 
Last Review:  3/16/2017 2:48:51 PM
Specimen Type
Container & Volume
  Age Group   Container   Volume  
  0  - 8 Years LAVENDER TOP TUBE 0.5 ML
  8 Years - 15 Years LAVENDER TOP TUBE 3 ML
  15 Years - 18 Years LAVENDER TOP TUBE 3 ML
Label Reminders
  Be sure to include patient's name, medical record number, date and time of collection, and collector's initials.
  Deliver peripheral blood and bone marrow specimens to lab at ambient temperature. If there is a delay of more than 24 hours in delivery, refrigerate the sample. DO NOT FREEZE.
Causes for Rejection
  • Unlabeled specimens will be discarded and the requesting physician notified.

Turn Around Time -  Routine: 10 days   Stat: N/A
Reference Values
Mutation not detected.
  This assay uses PCR followed by an amplicon nucleotide length analysis to
detect insertion and deletion mutations that cause changes in allele length and result in
frame shifts in exon 9 of the CALR gene. Genomic DNA is first purified from a peripheral
blood or bone marrow specimen. PCR is then performed using fluorescently tagged
oligonucleotide primers that specifically amplify exon 9 sequences of the CALR gene.
The nucleotide length of the fluorescently tagged CALR gene amplicon is determined by
capillary electrophoresis on the ABI Genetic Analyzer. Fragements are sized using
GeneMapper Software (ABI) and the different sized alleles are assigned based on
fragment length. Sanger sequencing will be employed to further characterize or clarify
results of any specimen showing an atypical amplicon base pair size that is not
conforming to a frameshift mutation.

This test was developed and its performance characteristics determined by
Duke Clinical Molecular Diagnostic Laboratory. It has not been cleared or approved by
the U.S. Food and Drug Administration. The FDA has determined that such clearance
or approval is not necessary. This test is used for clinical purposes. It should not be
regarded as investigational or for research. This laboratory is certified under the Clinical
Laboratory Improvement Amendments of 1988 ("CLIA") as qualified to perform high
complexity clinical testing.
Clinical Significance and Interpretive Data
    CALR exon 9 frameshift mutations are present in approximately 25% of essential thrombocythemia (ET) and 35% of primary myelofibrosis (PMF) patients, and are mutually exclusive with JAK2 and MPL mutations. CALR mutations have been rarely detected in cases of JAK2 mutation negative polycythemia vera (PV), refractory anemia with ringed sideroblasts with thromobcytosis (RARS-T). The presence of a CALR mutation has been associated with longer overall survival in ET and PMF, and with a lower risk of thrombosis in ET, as compared to patients with JAK2 mutations.

Klampfl T, Gisslinger H, Harutyunyan AS, Nivarthi H, Rumi E, Milosevic JD, et al. Somatic mutations of calreticulin in myeloproliferative neoplasms. N Engl J Med. 2013 12/19; 2014/08;369(25):2379-90.

Nangalia J, Massie CE, Baxter EJ, Nice FL, Gundem G, Wedge DC, et al. Somatic CALR mutations in myeloproliferative neoplasms with nonmutated JAK2. N Engl J Med. 2013 12/19; 2014/08;369(25):2391-405.

Rumi E, Pietra D, Ferretti V, Klampfl T, Harutyunyan AS, Milosevic JD, 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):1544-51.

Broséus J, et al. Presence of calreticulin mutations in JAK2-negative polycythemia vera. Blood. 2014 Dec 18;124(26):3964-6. PubMed PMID: 25305205.

    Identification of the CALR mutation in patients will provide another
molecular marker of classifying myeloproliferative disorders in order to improve
treatment options and care management.
    This test detects only CALR exon 9 frameshift mutations. Other mutations that may occur in the CALR gene would not be detected by this assay. Mutations or polymorphisms in the DNA oligonucleotide primer binding regions, poor DNA quality, insufficient DNA quantity or the presence of PCR inhibitors can result in uninterpretable or (rarely) inaccurate results. The sensitivity of this assay is 2.5%. If cells harboring the CALR mutation make up less than 5% of all granulocytes in this specimen they may not be detected by this assay. Poor genomic DNA quality or quantity, the presence of PCR inhibitors, and mutations or polymorphisms in the PCR primer binding sequences can result in uninterpretable or (rarely) inaccurate results. For additional information or for help interpreting the results of this test, clinicians should contact the DUHS Clinical Molecular Diagnostics Laboratory.
Related Tests
Test Synonyms
  Synonym(s): CALR
Molecular Diagnostics Laboratory

Medical Director:
 Michael Datto, M.D., Ph.D.
 Phone: 919-684-6965
Lab Director:
 Catherine Rehder Ph.D, FACMG
 Phone: 919-613-8434
Lab Director:
 Siby Sebastian Ph.D., DABMG
 Phone: 919-613-8432

 Wadsworth Bldg, Cytogenetics, Rm 0220
 2351 Erwin Rd
 Durham,  NC  27705
 Phone: 919-684-2698
 FAX: 919-668-5424

Performing Times: