Dec 29, 2015




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Molecular Diagnostics

Calreticulin (Exon 9) by PCR

Calreticulin (Exon 9) by PCR (CALR) Molecular Diagnostics Lab Test

Name: Calreticulin (Exon 9) by PCR

Test Name: Calreticulin (Exon 9) by PCR

Health Link Test Code: CALR

LIS Test Code: CALR

CPT Code(s): 81219

Methodology: Real-Time PCR by fluorescent capillary electrophoresis

Clinical Information:

In the absence of a JAK2 mutation, analysis of the calreticulin (CALR) gene aids in the diagnosis of a great majority (~80%) of myeloproliferative neoplasms (MPN), such as essential thrombocythemia (ET) and primary myelofibrosis (PMF). Deletions or insertions in Exon 9 of CALR have been found to be the second most frequent genetic mutation in MPN after JAK2, seem to be mutually exclusive with JAK2 and MPL mutations and have not been reported in polycythemia vera (PV) cases. MPN with CALR variants have been associated with a better clinical course than those with JAK2 mutations.


Days Performed: Once a week.

In-Lab Turnaround Time: 10 days.

Stat In-Lab Turnaround Time: Not available stat.

Specimen: Blood or bone marrow

Collection Container: Lavender top

Collection Instructions:

Many insurers require a prior authorization (PA) for this test. Please check patient coverage and send a copy of the PA form to the lab. This specimen will not be drawn until prior authorization has been completed. Please contact UWHC Test Referral office at (608)262-6388 prior to sample collection or for questions.

For UWHC - Ordering source must fill out the Referral Screening Flow Sheet prior to specimen collection.

For UWMF - Ordering source must fill out the UWMF Genetic Lab Request prior to specimen collection.

Collection Volume: 4 mL

Pediatric Collection Volume: 2 mL

Stability Ambient:

24 hours

Stability Refridgerated:

7 days

Stability Frozen:

Not acceptable

Sample Analyzed: Whole Blood

Testing Volume: 2 mL

Pediatric Testing Volume: 1.2 mL

Specimen Processing:

Do not centrifuge sample.

Specimen Transport:

Transport specimen to laboratory immediately. Refrigerate specimen if not delivered immediately. Do not freeze sample.


Not Detected

Interpretation Type: Expected Results

Test Limitations:

Sensitivity limit is 10-20% allele burden. 

Additional Information:

The Molecular Diagnostic Laboratory will cancel any calreticulin request on a patient that had a detected JAK2 V617F result.


For samples that are tested for Calreticulin (Exon 9) Mutation a qualitative result of"Detected" or "Not Detected" will be reported.


A result of 'Not detected" does not rule out the presence of the Calreticulin (Exon 9) Mutation. False negative results may be due to the presence of calreticulin mutation below the sensitivity of the assay or to inhibitory substances that may be present in the specimen. Inadequate specimen collection, processing and storage may invalidate test results. This test should not be used as the only criterion to form a clinical conclusion. Instead, results should be correlated with other test results, patient symptoms and clinical presentation. 


 The performance characteristics of this test were validated by UWHC Clinical Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. The UWHC Clinical Laboratories is authorized under Clinical Laboratory Improvement Amendments (CLIA) to perform high-complexity testing.


 A written interpretive report is provided by the laboratory.


 A professional fee is associated with this test.