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Alternative Name
CALR, calreticulin
Test Description

Fragment analysis of exon 9 of the CALR (calreticulin) gene for enhanced detection of low levels of insertion/deletion mutations. Automatic reflex to bi-directional sequencing will be performed for positive samples that are not Type 1 and Type 2 mutations and results will be reported out in an addendum. Testing is approved for specimens from the state of New York. Read more about the CALR Mutation Analysis.

Clinical Significance

CALR mutation analysis aids diagnostic confirmation of Philadelphia-chromosome negative and JAK2/MPL-mutation negative MPN. CALR mutations are mutually exclusive with JAK2 and MPL mutations, and are detected in peripheral blood in the majority (~70-85%) of essential thrombocythemia (ET) and primary myelofibrosis (PMF) cases that are JAK2- and MPL-mutation negative. CALR mutations are not reported in polycythemia vera (PV) and can distinguish ET and PMF from PV. Presence of CALR mutations is also associated with a better clinical course than JAK2 mutations.

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)*
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.