CALR (Calreticulin) Exon 9 Mutation Analysis by PCR

Also known as: CALR

Clinical Use

Use

This test is utilized for diagnostic and prognostic information in patients with myeloproliferative neoplasms (MPNs) when JAK2 testing is negative. Insertion/deletion mutations in exon 9 of the CALR gene result in a frameshift and are commonly found in cases of MPNs, essential thrombocythemia (ET), and primary myelofibrosis (PMF) lacking JAK2 V617F mutations. The test is particularly valuable in cases where standard markers are not detected, providing a pathway to diagnosis and tailored treatment management.

Special Instructions

Not provided.

Limitations

The test does not detect mutations in other regions of the CALR gene or mutations in other genes. It has a limit of detection of 5% mutant alleles for type 1 or 2-like variants and common noncanonical variants. The 1-bp deletion variant in Exon 9 cannot be detected or reported due to methodological limitations. Results should be interpreted in the broader clinical context and should not solely be used for a diagnosis of malignancy.

Test Details

New York Approved

Methodology

PCR-based (PCR)

Biomarkers

No genes

Gene

Mutation

Mutation • Categorical (e.g., Positive / Negative / Indeterminate)

LOINC Codes

Result Codes

35474-6 - Gene XXX Mut Anl Bld/T
31208-2 - Specimen source

Result Turnaround Time

2-9 days

Specimen

Whole Blood

Volume

5 mL

Minimum Volume

1 mL

Container

Lavender (EDTA) tube

Collection Instructions

Do not freeze. Transport 5 mL whole blood.

Storage Instructions

Refrigerated

Causes for Rejection

Plasma, serum, FFPE tissue blocks/slides, or frozen tissue. Specimens collected in anticoagulants other than EDTA. Clotted or grossly hemolyzed specimens.