Analytic Time

2 - 7 days

MiChart Code
CALR Mutation
Soft Order Code

Test Updated:


Primary Myelofibrosis (PMF)
Essential Thrombocythemia (ET)

Looking to order a test?

We’ve provided helpful links to make ordering easy.

Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Test Overview

Test Methodology

Polymerase chain reaction (PCR) with fragment analysis by capillary electrophoresis. Mutation confirmation by Sanger sequencing is performed on select cases.

Test Usage

CALR gene mutations occur at a frequency of 20-30% in primary myelofibrosis (PMF) and essential thrombocythemia (ET). Testing for CALR mutations can aid in the diagnosis of these myeloproliferative neoplasms. CALR mutations are typically exclusive of the JAK2 V617F mutation and are common (~50-75%) in PMF and ET cases that test negative for JAK2 V617F. The utilization of JAK2 V617F, CALR, and also MPL mutation testing provides detection of a clonal marker in the majority (>85%) of patients with PMF and ET. This CALR mutation test qualitatively detects all CALR exon 9 insertion and deletion mutations to a sensitivity of 2-5% mutant allele.

Reference Range

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect blood or bone marrow in a lavender top tube. Refrigerate and send intact blood or bone marrow specimen within 48 hours of collection. Fresh cell suspensions in RPMI should be refrigerated and sent, preferably within 48 hours. Frozen cell suspensions – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice.

Lavender Top Tube
Normal Volume
5 mL EDTA (lavender) whole blood; 3 mL EDTA (lavender) bone marrow; Fresh/frozen cells in RPMI. Extracted DNA is also acceptable if extracted in a CLIA certified laboratory.
Minimum Volume

Billing Information

CPT Code
Pro Fee Code

Have More Questions?

Explore our helpful billing resources:

Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.