CALR Gene Mutation Analysis

Mutations in the calcium-binding endoplasmic reticulin chaperone protein, calreticulin (CALR), have been shown to be common in patients with myeloproliferative neoplasms (MPN), exclusively to those without JAK2 and MPL mutations. Approximately 70% of patients with JAK2-negative essential thrombocythemia (ET) and 60-90% of patients with JAK2-negative primary myelofibrosis (PMF) harbor mutations in the CALR gene. CALR mutations are not reported in polycythemia vera (PV) and can distinguish ET and PMF from PV. The detection of a CALR gene mutation may aid in the diagnostic confirmation of Philadelphia-chromosome negative and JAK2/MPL-mutation negative MPN, and help distinguish MPN clonal disease from a benign reactive process. The presence of a CALR gene mutation also predicts for a better clinical course with a lower thrombotic risk and longer overall survival relative to those with a JAK2 V617F mutations. This assay will specifically detect mutations in the exon 9 of the CALR gene by fragment length analysis and bi-directional sequencing. The test sensitivity of this assay is approximately 1-5% by fragment length analysis and 20% by bi-directional sequencing.

Sample Requirements

2-3 mL whole blood or bone marrow in purple top EDTA tube

Sample Handling

Blood or bone marrow samples should be refrigerated or kept cold. Samples should never be frozen. Specimens being sent from outside facilities should be packaged according to standard medical safety practices with a cold pack. The specimen should be shipped by overnight priority (scheduled to arrive by Friday AM at the latest).

Shipping Address:

Center for Human Genetics Laboratory
10524 Euclid Ave, 6th Floor
Cleveland, OH 44106

For local samples, please call Client Service (216-844-5227) to arrange for sample pick-up.

Turn Around Time

5 – 7 days

CPT Codes


Please submit a completed Hematology/Oncology Specimens requisition for each sample.